Electrochemical properties were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in DCM and the resulting voltammograms are shown in Figure while the summary of electrochemical properties is found in Table . Upon scanning anodically, TPI undergoes a reversible oxidation at 1.08 V (E OX 1/2). Previously TPI oxidation was reported at 1.54 V (E OX onset) in DMF. With the introduction of donor groups, a new, cathodically shifted oxidation wave appears at 0.80 V and 0.62 V for DMAC-TPI and PXZ-TPI, corresponding to the oxidation of the DMAC and PXZ donors, respectively, the former being pseudo-reversible while the latter being reversible. The TPI-centred oxidation anodically shifts to 1.16 V and 1.17 V, becoming less reversible. In case of PTZ-TPI no TPI-centred oxidation is observed, instead a new oxidation wave registered at 0.85 V (E OX 1/2). The corresponding ionization potentials (IP) for TPI, DMAC-TPI, PXZ-TPI, and PTZ-TPI are 6.08 eV, 5.80 eV, 5.62 eV, and 5.61 eV, respectively. No reduction waves were observed within the electrochemical window, revealing the weak electron-accepting nature of the TPI. Therefore, the electron affinities (EA) were estimated using optical bandgaps at 2.45 eV, 2.24 eV, 2.31 eV, and 2.06 eV for TPI, DMAC-TPI, PXZ-TPI, and PTZ-TPI, respectively. The inclusion of the donor groups resulted in a destabilization of the LUMO and a decrease in the EA value of TPI by ca. 0.2 eV, a trend that is captured by DFT where the LUMO energies were destabilized by ca. 0.2-0.3 eV with donor introduction. eV. (f) Electron affinities were estimated using formula EA = |IP -E G opt|. UV/Visible absorption spectra were recorded in 10 -5 M toluene solutions and are shown in Figure . TPI shows a single absorption band located at λabs 291 nm (ε = 36 × 10 3 M -1 cm -1 ). DFT predicts this state to be a locally excited (LE) state (Figure ). All compounds showed no new features but did exhibit slight broadening of the characteristic TPI absorption band. The absorption spectrum of DMAC-TPI resembles that of TPI, with slightly increased molar absorption at 291 nm (ε = 46 × 10 3 M -1 cm -1 ). DFT predicted S1 state of ICT nature at 358 nm with low oscillator strength (f) value of 4.8 × 10 -3 . This was not observed in TPI emits at lPL of 382 nm with full width at half maximum (FWHM) of 0.51 eV (64 nm) in toluene (Figure ). The emission spectrum of DMAC-TPI is slightly narrower and the peak is only 6 nm (0.05 eV) redshifted compared to that of TPI, which is an indication that upon photoexcitation at 300 nm, emission from a TPI-based LE state dominates in both compounds. The emission spectrum of PXZ-TPI is 36 nm (0.28 eV) red-shifted compared to that of TPI however, both DMAC-TPI and PXZ-TPI emission spectra show the same FWHM of 0.44 eV (63 nm) and 0.42 eV (64 nm), respectively, indicating just a weakly extended conjugation in the chromophore (TPI), rather than occurrence of typical broad intramolecular charge transfer (ICT) band. PTZ-TPI showed dual-luminescence, originating from LE emission from each of TPI and PTZ in this compound (Figure ). Apparently, in this compound both chromophores are photoexcited simultaneously and there is no observable ICT emission. Changing the polarity of the solvent did not have any impact on the shape and position of TPI emission, while the emission spectra of both DMAC-TPI and PXZ-TPI showed modest positive solvatochromism (Figure ). For PTZ-TPI, moving to more polar solvents resulted only in relatively higher contribution from the TPI emission to the overall PL, and no ICT emission band was detected.