potentially suppresses vibrational motions that may be more active in the more fluid zeonex host (FPL 20%). Still, the large mCP FPLs cannot be fully explained, and we suggest that it originates from intermolecular interaction between the guest and host molecules, forming an exciplex species. Heteromolecular interactions are possible based on the measured HOMO/LUMO values of the three emitters (-6.13/-3.07, -6.15/-3.19, and -6.00/-2.95 eV for dBr-tBu-DiKTa, tBr-DiKTa, and Mes3-DiKTa respectively) and the mCP host (-5.9/-2.4 eV) .