As shown in Figure , the SS PL of DDiKTa-A exhibits a temperature dependence in 2-MeTHF solution (123-298 K). DDiKTa-A shows a structureless orange emission at 577 nm at RT and when the temperature decreases to 163 K there is a gradual red-shift of the emission to 638 nm. This phenomenon can be attributed to the increased dielectric constant of 2-MeTHF upon cooling, which stabilizes the LRCT state of DDiKTa-A. When the temperature is close to the glass transition temperature of 2-MeTHF (131-142 K) the emission blue-shifts, ultimately reaching 566 nm at 123 K. This shift is attributed to the longer geometry relaxation time in frozen 2-MeTHF. Importantly, this observation suggests that the red-shifted emission is a result of the sensitivity of the singlet state to the polarity of the environment, rather than aggregation during the cooling process.