to their FPL in PhCzBCz films (ΦPL of 60 and 65%, and λPL of 477 and 476 nm for tDPABT1B and tDPABT2B, respectively). The narrowband emission of each of tCzBT1B, tCzBT2B, tDPABT1B, and tDPABT2B is preserved in the solid state, with FWHM of 0.15 eV (30 nm), 0.16 eV (31 nm), 0.14 eV (26 nm), and 0.15 eV (28 nm), respectively. The slightly bathochromically shifted and broadened PL spectra compared to the emission in toluene is likely due to contributions from aggregates at the doping concentrations used, a behavior that was also observed in the films of BTC-BNCz. Compounds tCzBT1B and tCzBT2B have similar S1/T1 values of 2.63/2.54 eV and 2.64/2.55 eV, whereas the corresponding values for tDPABT1B, and tDPABT2B are destabilized to 2.70/2.59 eV and 2.71/2.59 eV, respectively (Figure ). The four emitters possess ΔEST values below 0.12 eV, which are similar to those measured in frozen 2-MeTHF and to the SCS-ADC calculations. The temperature-dependent time-resolved PL decays of the four emitters under vacuum reveal a notable increase in the intensity of the delayed emission as the temperature increases (Figure ), a characteristic hallmark of TADF. At room temperature, the TR PL decays of tCzBT1B and tCzBT2B