TCzPhCor to TDMACPhCor and TPXZPhCor, coinciding with their decreasing optical gaps (Figure ). A stronger positive solvatochromism is observed in TPXZPhCor compared to TDMACPhCor (Figure ), which is almost absent in TCzPhCor. As shown in Figure , the Lippert-Mataga study reveals that the emissive state of TCzPhCor is of dominant LE character, while the emissive state of TDMACPhCor is better described as having hybrid LE and CT character, that of TPXZPhCor is of CT character, matching well with the calculations (Figure and). The related experimental absorption and PL spectra and calculated parameters from the Lippert-Mataga study are presented in Figure and Table . Notably, a linear relationship between the Stokes shift (ua-uf) and the orientational polarizability f was observed for TCzPhCor and TPXZPhCor (Figure ). The relatively small slope for TCzPhCor and unstructured emission imply that the S1 state possesses a moderate degree of CT character, reflected in a dipole moment, μe, of 11.4 D calculated according to the Lippert-Mataga equation (see Supporting Information for details). For TPXZPhCor, the slope of the Lippert Mataga plot is much steeper, which implies a much stronger CT character to the S1, linked with an associated μe of 24.7 D. The picture for TDMACPhCor is more complex as the Lippert-Mataga plot reveals two distinct regimes with μe of 16.9 D and 33.0 D. Such behavior is characteristic of an excited state of mixed LE and CT character (HLCT). The ΦPL values of TCzPhCor, TDMACPhCor, and TPXZPhCor in aerated toluene are 34%, 18%, and 16%, respectively, which essentially do not change in degassed toluene (Table ). The time-resolved PL decays are monoexponential, with PL lifetimes, tPL, in the nanosecond regime (Figure ). The ΦPL and tPL values rule out emission involving triplet excitons. The DEST for TCzPhCor, TDMACPhCor, and TPXZPhCor, determined from the onsets of prompt and delayed emission in toluene at 77 K, are 0.59 eV, 0.54 eV, and 0.34 eV (Figure ), respectively. Such large DEST values rule out the possibility of TADF. The similar phosphorescence spectra in the three compounds recorded in toluene at 77 K indicate that the nature of the T1 state is the same and localized on the TPhCor core (Figure ). We next investigated the photophysical properties of the three emitters in PMMA at a 1 wt% doping concentration. As shown in Figure , the steady-state PL spectra of TCzPhCor, TDMACPhCor, and TPXZPhCor show structureless emission at lPL of 450 nm, 465 nm, and 500 nm, respectively, with associated tPL of 9.8 ns, 25.2 ns, and 30.8 ns, respectively (Figure ). RTP spectra of TCzPhCor, TDMACPhCor, and TPXZPhCor were acquired across a time-gated window of 30-200 ms, with maxima, lPh, centered at around 580 nm, 530 nm, and 550 nm, respectively. The corresponding phosphorescence lifetimes (τPh) are 573.0 ms, 286.1 ms, and 34.6 ms, respectively (Figure ). The low-temperature phosphorescence (LTP) spectra at 77 K are centered at around 575 nm, 576 nm and 580 nm for TCzPhCor, TDMACPhCor, and TPXZPhCor, respectively (Figure ).