The photophysical properties of TPA-H and its supramolecular assemblies were first evaluated by ultravioletvisible (UV-vis) absorption and photoluminescence (PL) spectra. As illustrated in Figure , a main absorption profile of TPA-H is observed at 465 nm and its maximum PL band centers at 654 nm in pure dimethylsulfoxide (DMSO) solution. AIE behaviors of TPA-H were investigated in DMSO and dichloromethane (DCM) mixtures. TPA-H emitted weak red fluorescence in DMSO. When adding poor solvent DCM to the solution gradually, increased fluorescence was observed accompanied by some hypsochromic shift in PL spectra due to twisted intramolecular charge transfer (Figure ). Above results demonstrated TPA-H is AIE-active. Then, theoretical calculations were carried out to optimize its molecular structure and orbital by using density functional theory (DFT) methods (Figure ). The whole molecule adopted a twisted conformation due to introduction of triphenylamine unit, which is favorable for efficient emission in the aggregated state. The highest occupied molecular orbital (HOMO) of TPA-H mainly located on the triphenylamine moiety, while the lowest unoccupied molecular orbital (LUMO) concentrated on the diazosulfide and phenyl rings. The energy gap was computed to be 1.90 eV. In addition, the lowest energy gap of singlet and triplet states (ΔES1-T2) of TPE-H was computed to be 0.06 eV, which is favorable to promote intersystem crossing (ISC) to triplet state. TPA-H fluoresced brightly with a QY of 9.0% in aqueous medium. Upon addition of 2.0 equivalents (eq.) of SAC4A, the fluorescence intensity dramatically decreased with a QY of 0.85%, implying strong electrostatic interactions (Figure ). Therefore, it is anticipated that TPA-H and SAC4A formed supramolecular complexes (TPA-H⊂SAC4A). PL titration was carried out to further verify the host-guest assembly. With enhancing the concentration of SAC4A, the fluorescence intensity of TPA-H gradually reduced and achieved equilibrium until 2.0 equivalents of SAC4A was added (Figure ). After supramolecular assembly of SAC4A and TPA-H, the zeta potential of the resultant nanoparticles changed from ∼15.0 mV for TPA-H to ∼-26.4 mV for TPA-H⊂SAC4A due to the negative charges of sulfonate motif in SAC4A (Figure ). Additionally, the time-resolved fluorescence decay curves of TPA-H and its supramolecular complexes were tested. TPA-H showed a lifetime of 1.78 and 1.90 ns in DMSO solution and powders, respectively. After selfassembly with SAC4A in aqueous solution, the lifetime of TPA-H⊂SAC4A decreased to 1.22 ns (Figure and). Dynamic light scattering (DLS) data showed that TPA-H formed micro-assemblies with a mean diameter of about 1554 nm in water solution (Figure ). After complexation with SAC4A, the aggregate size decreased to 243 nm owing to dissolution enhancement by water soluble of SAC4A (Figure ). Then, the photostability of supramolecular nanomaterials was evaluated under different times, different pH values and various species like HPO4 -, CO3 -, Mg 2+ , Na + , Cu 2+ , K + , Ca 2+ , they all showed little influence on their PL properties (Figure ). To explore the potential self-assembly mechanism, 2D COSY NMR, 1 H NMR titrations, and 2D NOESY NMR of TPA-H with SAC4A were implemented in d6-DMSO. Through analysis of 2D COSY NMR, their specific protons are clearly characterized (Figure ). When adding 0 to 2.0 equivalents of SAC4A to TPA-H, the signal of the methyl proton (Ha), phenyl ring protons (Hb and Hc) and vinyl double bonds (Hd and He) of TPE-H presented evident upfield-shifts by -0.036, -0.035, -0.031, -0.019 and -0.018 ppm (Figure and Table ) showing effective shielding effect by the aromatic rings of SAC4A. It was properly inferred that the quaternary ammonium moiety was inserted in the cavity of SAC4A. The protons of triphenylamine and diazosulfide unit showed minor change, implying these segments kept away from the cavity. Due to the inclusion of TPA-H, the phenyl ring proton Hf and Hg of SAC4A gave an obvious downfield shift by 0.015 and 0.011 ppm (Figure ). The 2D NOESY spectrum of mixture of TPA-H and SAC4A showed an obvious NOE signal between vinyl proton (He) of TPA-H and phenyl proton (Hf) of SAC4A, indicating that TPA-H is partially inserted in the cavity of SAC4A (Figure ). Sodium dithionite (Na2S2O4) as a reducing reagent was selected to verify the reduction of azo group in SAC4A by using HRMS spectroscopy. Upon addition of Na2S2O4 to SAC4A solution, the N=N double bond rapidly decomposed to form p-aminocalix [4]arene (Figure and). Then, the reaction between TPA-H⊂SAC4A and sodium dithionite was studied by using UV and PL spectroscopy. As shown in Figure , the UV intensity was evidently increased after complexation with SAC4A in aqueous medium. When sodium dithionite was added in the complex of TPA-H⊂SAC4A, the absorption band of the mixture showed a similar profile with TPA-H. Meanwhile, the red fluorescence at 654 nm was turned on gradually over time (Figure ). Above data supported our hypothesis that azo group of SAC4A was broken to release the included TPA-H and emit bright fluorescence, which further stimulates us to study their hypoxia-responsive bioimaging. The HeLa cells were incubated in normoxic (20% O2) and hypoxic (less than 0.1% O2) conditions with the same concentration of TPA-H⊂SAC4A nanomaterials. Figure and Figure revealed that the fluorescence intensity enhanced more than 2-fold in hypoxia than that in normal oxygen concentration. This indicated that SAC4A is decomposed in hypoxic microenvironment and released TPA-H from its cavity. ROS generation efficiency is a key factor to evaluate the PDT ability. The whole ROS capability was assessed by indicator 2,7-dichlorodihydrofluorescein (DCFH-DA) under white light. DCFH-DA was weakly emissive under light irradiation (Figure and Figure ). While, its fluorescence intensity was drastically increased with a 54-fold enhancement after illuminating for 6 s, proving a rapid and high ROS generation efficiency. After complexation with SAC4A, the ROS generation efficiency was largely suppressed. To determine the species of ROS, 9,10-anthracenediylbis(methylene)-dimalonic acid (ABDA) was utilized to detect type II ROS 1 O2 through using absorption spectra. As shown in Figure and Figure , ABDA was almost no change upon exposure to white light. While, upon addition of TPA-H, a large decrease in the absorption profile was observed with a 91% of ABDA consumption. Interestingly, the supramolecular complexes TPA-H⊂SAC4A totally inhibited the 1 O2 generation. Then, we verified that if TPA-H can produce type I ROS, dihydrorhodamine 123 (DHR123) was first selected as radical ROS indicator to monitor O2 •-. From the PL spectra we can see that DHR123 was almost unchanged under illumination (Figure and Figure ). However, the mixture of DHR123 and TPA-H showed a sharp enhancement in PL intensity. After host-guest interaction with SAC4A, the O2 •-generation efficiency largely decreased. In addition, type I ROS species were also explored by electron spin resonance (ESR) spectra using 4-amino-2,2,6,6-tetramethylpiperidine (TEMP) and 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as spin-trap probes for 1 O2 and free radicals, respectively. Compared with the dark state, TPA-H presented strong 1 O2 generation (Figure ), and no ESR signals were attained in TPA-H⊂SAC4A system, which is coincident with absorption data. Moreover, TPA-H and its supramolecular assemblies showed evident O2 •-signals after interaction with DMPO in methanol (Figure ) and no obvious OH• radical response was observed in water (Figure ). Thus, such results indicated that TPE-H can efficiently generate 1 O2 and O2 •- ROS. While, SAC4A can largely restrain 1 O2 generation after interaction with TPA-H. Then, DCFH-DA was used to detect intracellular ROS generation (Figure ). After treating with DCFH-DA and TPA-H, bright green fluorescence was observed in HeLa cells under light excitation, while no fluorescence was detected in the dark state and DCFH-DA group, implying that TPA-H can produce ROS under light illumination in living cells. TPA-H exhibited remarkable 1 O2 radical signals after interaction with TEMP in water (D), exhibits a small amount of O2 •-radical signaling after interaction with DMPO in methanol (E) and no OH• radical signaling after interaction with DMPO in water (F). TPA-H⊂SAC4A exhibits obvious O2 •-radical signaling (E) after interaction with DMPO in methanol and no 1 O2 (D) and OH• (F) radical response in water. Light power: 100 mW cm -2 .