The photophysics of the emitters were then investigated in degassed toluene solution (Figure ). ). These lifetimes are comparable to those previously reported in the literature for the same compound. As expected, the delayed component disappears after the solution is exposed to air. The derivatives decorated with electron-donating groups have slightly longer tp than DMAC-TRZ, with mono-exponential decays of 28.70 ns and 28.09 ns for t BuPh-DMAC-TRZ and OMePh-DMAC-TRZ, respectively (Figure ). Their degassed solutions possess much shorter delayed lifetimes than DMAC-TRZ, with monoexponential td of 2.39 µs, and 1.49 µs, for t BuPh-DMAC-TRZ and OMePh-DMAC-TRZ, respectively, which each disappear when the solution is exposed to air. This implies a more efficient reverse intersystem crossing rate (kRISC) for these two emitters, as both the amplitude and lifetime of the delayed component improves. The TRPL of CF3Ph-DMAC-TRZ and dPh-DMAC-TRZ appears to behave in the opposite manner with shorter tp of 10.9 ns and 15.4 ns, respectively (Figure ) and longer td and biexponential decay kinetics (average td of 20.7 µs and 25.8 µs, respectively), which also disappear after exposure to air. There is no delayed emission observed for CNPh-DMAC-TRZ and the tp is 8.24 ns, which decreases to 6.53 ns when exposed to air due to a small degree of singlet quenching caused by the presence of oxygen. The short prompt lifetime is consistent with emission from a LE state.