The detailed synthesis procedure, characterization, and electrochemical data of 1B-CzCrs and 2B-CzCrs are provided in supporting information (Figs. S1-19, Table ). The ground-state and excitedstate geometries of 1B-CzCrs and 2B-CzCrs were calculated using Density Functional Theory (DFT) and the post Hartree-Fock methods, respectively. The HOMO-LUMO energy gaps for 1B-CzCrs and 2B-CzCrs were calculated as 3.88 eV and 3.77 eV, respectively (Fig. ). These values are smaller than those reported for 1B-DTACrs and 2B-DTACrs (4.03 and 3.91 eV) due to the increased conjugation that results from the incorporation of the fused carbazole moiety (Table ). This trend supports the experimentally obtained values, which are 3.13 and 3.10 eV for 1B-CzCrs and 2B-CzCrs, respectively, and 3.17 and 3.05 eV for 1B-DTACrs and 2B-DTACrs, respectively (Table ), especially for the monoborylated counterparts. The oscillator strength of the S0-S1 transition of 1B-CzCrs is larger (0.27) than that of 2B-CzCrs (0.16), while the ΔEST are essentially the same (0.16 and 0.17 eV) (Table ).