With increasing bromine content, SOCME increase from 0.28 to 0.30 and 0.46 cm -1 for S1-T1, 1.34 V), again the result of the inductively electron-withdrawing bromine substituents. The corresponding HOMO and LUMO energies are calculated to be -6.00/-2.95, -6.13/-3.07, and -6.15/-3.19 eV, respectively, where the trend matches well with the DFT calculations (Figure ). The data are summarized in Table .