b. The lifetime is below the resolution limit of our TCSPC setup. Next, we turned to thermal effects on the radiative deactivation pathways using temperature-dependent TCSPC in O2-free MeTHF (Figures S46 and S47 and Table ). For mPhTc2, the prompt (S1S0)rel lifetime is below the instrumental time resolution. The lifetime of the second component, that is (S1S0)(T1T1) CT , displays little temperature dependence. The remaining long lifetime, namely that of (T1T1), increases from 50.2 ns at 300 K to 148.0 ns at 80 K with relative amplitudes of 68.5 and 18.8%, respectively.