The time-resolved PL (TR PL) decays in toluene are shown in Figure . The emission decays with biexponential kinetics, with prompt lifetime, tp, of 16.3 ns and delayed lifetime, td, of 41.0 µs under N2; the delayed emission was quenched upon exposure to air (Figure ). The FPL decreases from 44 to 36% upon exposure to air. The inferred kinetics rate constants are summarized in Table and the rate constant for RISC, kRISC, is 1.63×10 4 s -1 . Notably, no delayed lifetime in toluene solution was observed for DiKTa, DDiKTa, and DIDOBNA-N.