When placed under vacuum, the broad PL band was enhanced with peak maxima at 403 nm and 426 nm, indicating the most likely involvement of triplet excited states. Time-gated PL measurements (3 ms delay) detected the RTP spectrum of Cz-C-PTZSO 2 , where dual emission bands centered at 470 nm and 530 nm can be observed (Figure ), together with associated average t Ph values of 60.1 ms and 89.6 ms (Figure ), respectively. Figure shows RTP spectra collected at different delay times, which demonstrate that the RTP at 470 nm decays faster than that at 530 nm, reflecting the results of the RTP lifetime measurements (Figure ). These dual emission bands match well with the enhanced LE emission and the emission tail presented in the steady-state PL spectra in vacuum. The phosphorescence spectrum recorded at 80 K blue-shifts to 475 nm and is dominated by the structured blue emission band, whose low-temperature phosphorescence (LTP) lifetime is prolonged to 836.7 ms (Figure ). In line with the proposed multiple phosphorescence model (Figure ), we ascribe the dual RTP emission to the result from phosphorescence from each of the Cz-Ph and PTZSO 2 moieties.