The calculated excited singlet (S1) and triplet (T1) energies of AZB-Ph-TRZ are 3.03 eV and 2.93 eV, respectively, which are stabilized to 2.86 eV and 2.84 eV for AZB-TRZ, presumably due to its electronically different and stronger acceptor. These states are also stabilized when stronger donors are used as is the case with azasiline-Ph-TRZ (S1=2.80 eV; T1=2.79 eV) and DMAC-TRZ (S1=2.56 eV; T1=2.55 eV). The corresponding calculated ∆EST values are 0.10 eV for AZB-Ph-TRZ and 0.02 eV for AZB-TRZ, indicating these compounds should exhibit TADF. These values are similar to those calculated for azasiline-Ph-TRZ and DMAC-TRZ, which is not surprising given the similar perpendicular conformation adopted in the latter two (both with ∆EST of 0.01 eV), while the ∆EST of Cz-Ph-TRZ is much larger at 0.38 eV, the result of its less twisted structure. The estimated oscillator strength (f) for the S0→S1 transition is 0 and 0.0013 for AZB-Ph-TRZ and AZB-TRZ, respectively, reflecting the very weak electronic coupling between donor and acceptor groups due to the near orthogonal conformation in the compounds.