Notably, there is significant LE emission from PTZ at around 380 nm for PTZ-Nap (Figure ) revealing that electron transfer to the CT state is slow compared to radiative decay. The experimentally calculated DE ST at 77 K deviates from the computed values (0.05 eV and 0.24 eV, respectively, Figure ), which we attribute to different accessible relaxed conformers at room temperature compared to those at 77 K. Combining the above-discussed results in PMMA, mCP and 2-MeTHF glass, we rationally conclude that the T 1 emission can be regulated by the host-guest interactions that govern the conformational landscape of PTZ-Nap.