While the low temperature (LT) measurements permit a robust estimation of ∆EST, noting that in the vast majority of TADF compounds the S1 state has greater CT character than T1, this measurement will not accurately capture ES at room temperature. This is because CT states are stabilized as a function of solvent polarity and the greater the CT character, the stronger the stabilization of the state. As triplet states tend to show lesser CT character than singlets, the estimated ET = ES(RT -∆EST(LT) represents the outer bound value for what ET may be at room temperature. Thus, given the LRCT character of the S1 state of 4CzIPN the change in ET at room temperature is more pronounced than for the four DICz MR-TADF compounds (Table ). This implies that in DET reactions the spectral overlap between the PC* and the sub may change significantly, especially when the T1 state possesses some CT character. For MR-TADF compounds this stabilization effect is small given the SRCT character of the S1 and T1 states. MR-TADF emitters maintain their ET in polar solvents, while for 4CzIPN, the ET is much more stabilized. ). Given the moderately large EST, it is not uncommon for MR-TADF emitters to not show delayed emission in solution as non-radiative decay competes with RISC, while in the solid state this is largely suppressed and delayed emission becomes apparent. DiICztBu4 and DiICzMes4 have reported delayed fluorescence lifetimes, τDF, of 12.5 ms as 1 wt% doped films in mCP:TSPO 1:1 and τDF = 433 µs as 3 wt% doped films in mCP, respectively, while there was no observed delayed emission in solution.