Meanwhile, the intensity of the low energy phosphorescence in all five emitters shows a characteristic inverse temperature dependence (Figure and). To confirm that the roomtemperature phosphorescence originates from the T1 state, we additionally recorded the change in the time-gated PL spectra with temperature (Figure ). For 4NICz and 7NICz, the phosphorescence spectra do not change between 77 and 300 K, while for 5NICz the lPh remains the same, but the PL spectra are broadened at lower temperatures. In 6NICz and 6,10NICz, the shape of the phosphorescence at 300 K is partially masked by the contribution from the higher energy TADF, but the bump originating from RTP clearly matches the peak position of the phosphorescence at 77 K.