(S)-PCNCP and (S)-PCNTPA in dilute toluene solutions exhibit absorption maxima at 310 and 320 nm and photoluminescence (PL) peaks at 390 and 423 nm, respectively. In neat films, (S)-PCNCP and (S)-PCNTPA display robust PL emissions peaking at 404 and 439 nm, with high PL quantum yields (ΦPLs) of 91% and 85%, respectively. The doped films of 25 wt% (S)-PCNCP and 40 wt% (S)-PCNTPA in 2,6-bis(carbazol-9-yl)pyridine (PYD-2) host show nearly unchanged PL spectra, and excellent ΦPLs of 97% and 95%, respectively (Fig. and, and Supplementary Table ). The transient PL decay spectra of (S)-PCNCP and (S)-PCNTPA in toluene solutions under nitrogen reveal double exponential decay processes, with short mean PL lifetimes of 6.8 and 7.5 ns, respectively. Notably, apparent delayed components with extended lifetimes of 24.9 and 24.8 ns are observed under nitrogen, but get attenuated with lifetimes decreased to 6.4 and 7.9 ns under air (Fig. , Supplementary Fig. , and Supplementary Table ), indicative of the involvement of triplet states in the radiative decay process. In neat films, (S)-PCNCP and (S)-PCNTPA exhibit short mean PL lifetimes of 2.8 and 3.3 ns. The reduced yet discernible delayed components are detected under nitrogen, with reduced lifetimes of 6.2 and 6.4 ns. And the lifetimes of delayed components become slightly longer upon elevating the temperature from 77 to 300 K, as unveiled by the temperature-dependent transient PL decay spectra (Supplementary Fig. and, and Supplementary Table ). A similar trend is observed for these materials in doped films (Supplementary Fig. and Supplementary Table ). The fluorescence and phosphorescence spectra recorded at 77 K provide the S1-T1 energy splitting (∆EST) of 0.60 and 0.47 eV for (S)-PCNCP and (S)-PCNTPA in neat films, and 0.58 and 0.40 eV in doped films (Supplementary Fig. ). These findings reveal the absence of typical TADF property in these materials, but the delayed components with short lifetimes are likely induced by hRISC process , according to the theoretical calculation results.