First, the thermodynamic reversibility of imine-linked PDI polymers was tested by reacting NH2-PDI with 2-thiophenecarboxaldehyde in the presence of trifluoroacetic acid (TFA) in the dark to yield the corresponding imine (See Figure . Two-steps synthesis of BisAzaCoroneneDiimides (BACDs) conjugated polymers. The first step is the reversible formation of polyimines. The second step is an irreversible visible light triggered oxidative photocyclization, which locks the imines into a fused system and "freezes" the system into a kinetically stable conjugated polymer. Supplementary Information). After isolation, the product was subjected to the same reaction conditions with panisaldehyde, resulting in imine exchange and the coexistence of both imines (Scheme S1, Figure and). This demonstrates that imine-linked PDIs behave as dynamic covalent materials. Subsequently, the two-steps/one-pot polymerization of 1,6/7(NH2)2PDIs 1 and 2,5-thiophenedicarboxaldehyde 2 was developed to form a BACDthiophene polymer P(BACD-T) (Figure , Method A). The optimal polymerization conditions were determined to be 150°C in toluene at 50 mM under microwave irradiation, using TFA as a catalyst. A slight excess of 1 was used to form amine-terminated imine-linked PDI polymers. This solution was then exposed to visible light and subjected to oxidative rearomatization by the addition of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The amine-terminated material was further reacted with an excess of 2-thiophenecarboxaldehyde 3 as an end-capper, exposed to visible light, and oxidized again. The photocyclization steps of this sequence were conducted in a continuous flow photoreactor. Prior to its applications to polymer, this reaction demonstrated to be a highly selective, clean and efficient method for the preparation of AzaBenzannulated PDIs. We performed an optimization of the photocyclization on model dimer 4 obtained from the condensation of 2 equivalent of the diamine 1 on 1 equivalent of the ditopic aldehyde 3, to determine the ideal flow-rate and concentration for this reaction (Scheme S2, Figure ). Remarkably, the monitoring of the photocyclization by MALDI-TOF mass spectrometry revealed here again an efficient and clean process, with no decomposition or side reactions observed after exposure to strong white light. This importantly highlights the high photostability of the studied materials. Several polymerization attempts were performed at initial monomer concentrations of 6, 10, 30, 50 and 86 mM. The polymers were purified by precipitation and Soxhlet extraction and analyzed by size-exclusion chromatography (SEC) to determine their M ̅ n , M ̅ w , DP ̅̅̅̅ n , and dispersity index Đ (see Supplementary Information). Chromatograms revealed multiple populations for polymerization concentrations of 30 mM and below, but cleaner elution peaks were obtained above this threshold, leading to the selection of 50 mM as the optimal concentration for further studies. P(BACD-T) polymers produced by Method A were obtained in high yields and displayed increasing M ̅ n , M ̅ w , DP ̅̅̅̅ n with higher monomer concentrations, reaching M ̅̅̅ n values from 12.9 to 40.0 kDa, corresponding to DP ̅̅̅̅ n of 12 to 37 repeating units (Figure ). A near-linear relationship was observed between initial monomer concentration and M ̅ n . The dispersity Đ increased with M ̅ n but remained at a reasonable 1.8 for the 50 mM concentration. This method showed excellent reproducibility, with repeated polymerizations of P(BACD-T) at 50 mM yielding minimal deviation: M ̅ n = 22.6 ± 2.5 kDa, M ̅ w = 39.7 ± 6.1 kDa, DP ̅̅̅̅ n = 21 ± 2, and Đ = 1.8 ± 0.1. We attribute this consistent result to the first step involving dynamic covalent bonds, ensuring that, for a given set of reaction parameters, similar poly-imine populations are formed at thermodynamic equilibrium before being "frozen" by visible light. Additional insights into the polymer structure were revealed through infrared (IR) spectroscopy (See Supplementary Information, Figure ). Vibrational spectra of amine 1, aldehyde 2, and P(BACD-T) polymer synthesized at 50 mM and a model monomeric compound, 1,6/7-BACD-T2, were compared. In the high-wavenumber region, 1 exhibited broad peaks between 3500 and 3200 cm⁻¹, attributed to N-H bond vibrations. These IR absorptions were absent in the model compound 1,6/7-BACD-T2 and in P(BACD-T), indicating the successful transformation of NH₂ groups. In the carbonyl region, the spectra of 1,6/7-BACD-T2 and the P(BACD-T) polymer displayed similar vibrational profiles, without the aldehyde signature seen in the aldehyde monomer 3. It supported the successful polymerization with no detectable amount of amine-or aldehyde-terminated chains. Based on our previous work on the photoazabenzannulation reaction of PDIs and the results presented herein, we can state that this process produces welldefined BACD-based conjugated polymers, with no evidence of homocoupling, undesired terminations, or any residual reactive chain ends, an attractive combination of advantages for the synthesis of new n-type conjugated polymers. With this new methodology in hand, we prepared a range of five additional polymers from more complex aldehyde monomers: P(BACD-C) from 9-(2-Ethylhexyl)carbazole-3,6-dicarboxaldehyde, P(BACD-F) from 9,9-Dioctyl- To improve these results, we developed Method B, using chlorobenzene as a stronger solubilizing solvent for polycyclic aromatic derivatives, to overcome the eventual solubility limitations of poly-imines intermediates. We also adjusted the monomer ratio slightly to 1/0.94 to aim for longer polymer chains. Method B resulted in improvements across all materials (Figure ), with some results showing significant enhancements. P(BACD-F) afforded an insoluble material probably because of a high M ̅ n , P(BACD-C) improved its molar mass and the M ̅ n of P(BACD-TII) improved from 10.9 to a good value of 29.6 kDa. However, both P(BACD-IDTTB6) and P(BACD-DPP) remained highly polydisperse materials showing multiple peaks when analyzed by SEC and showed small M ̅ n < 10 kDa. We envisioned a new approach: Method C, a terpolymerization strategy, designed to address the two primary hypothetical limitations: a possible poor solubility of growing polymer chains and the possible low nucleophilicity of the diamine monomer 1. First, 2,5-thiophenedicarboxaldehyde was reacted with a small excess of 1 to form the dimer 4 (see Supplementary Information and Scheme S11). This highly soluble monomer, slightly electronically enriched by the thiophene core, was then polymerized with the previous aldehyde monomers using the reaction conditions of Method A (Figure and the success of this approach (Figure ). The SEC data of TP(BACD-T-IDTTB6) was much more satisfying even if a shouldering on the main elution peak remained. This demonstrates that depending on the monomer's nature and reactivity, the polymerization strategy can be adapted to reach the desired materials. The more difficult polymerization of the IDTTB6 fragment is attributed to its strong electron donor nature rendering the aldehydes poorly electrophilic. Although polymers produced by Method A/B and Method C are not strictly identical, the flexibility of both methods potentially enables the synthesis of a wide and diverse collection of new electron-deficient conjugated polymers by simply combining diamines 1 or 4 with any optoelectronically active bis-aldehyde monomers. The success of Method C, the terpolymer approach, opens the door to the easy synthesis of more complex terpolymers combining complementary redox-active chromophores in structure exhibiting a well-defined sequence. The 1 H NMR of the polymers performed in C2D2Cl4 showed only barely visible broad peaks, probably owing to strong intermolecular interactions in solution (Figure to S76). Thermogravimetric analyses were performed to probe the thermal stability of these BACD polymers. High degradation temperatures are crucial to ensure a good resilience to various device processing and fabrication methods. All polymers displayed excellent thermal stability with no degradation observed before 400 °C (Figure to S56). The optoelectronic properties of the new polymers were investigated by absorption spectroscopy in solution (CHCl3) and thin film, and Cyclic Voltammetry (CV). For the sake of clarity and space, we will limit the discussion here to the polymers that were obtained with a satisfying M ̅ n , but the complete optoelectronic characterizations of all polymers can be found in the Supplementary Information. respectively with high extinction coefficient of ε = 3.0, 1.4 and 3.8 × 10 -4 M -1 . cm -1 (Figure ). They absorb visible light up to 550 nm in solution. P(BACD-T) can be directly compared to its monomeric analogue 1,6/7-BACD-T2. The monomeric material showed a maximum around 373 nm spectra in CH2Cl2, and an overall absorption reaching only 530 nm, thus the polymerization of the motif leads to a significant red-shift. In films, red-shifts are observed, resulting from aggregation. No significant changes were observed after thermal annealing at 150 °C for 10 min. This could be explained by the fact that we used 1 as its regioisomeric mixture of 1,6 and 1,7 isomers, which results in regio-irregular polymers thus probably poorly crystalline in thin films. P(BACD-TII) shows a broad continuous absorption of UV and visible light up to 700 nm, with a maximum strongly absorbing with ε = 3.8 × 10 -4 M -1 . cm -1 . In films, a significant shoulder appears between 500 and 700 nm, reinforcing its absorption coverage tailing up to 800 nm. TP(BACD-T-TII) revealed a similar spectrum with a stronger shouldering around 450 nm (ε = 5.1 × 10 -4 M -1 . cm -1 ), reinforced and red shifted in thin-films. These two polymers display a quasipanchromatic absorption of visible light up to the NIR. P(BACD-IDTTB6) also strongly absorbs visible light with a maximum around 475 nm and tailing up to 700 nm in thin films. TP(BACD-T-DPP) shows a maximum at 410 nm and a broad peak at larger wavelength with two maxima at 660 and 706 nm. Its spectrum is red-shifted in film with an increase of absorption of the low-energy bands, allowing it to efficiently absorb all visible light up to 800 nm. A crucial photophysical properties of such materials is their photostability, which ensure that they will deliver long lasting and reproducible performances in devices.