PVA is a polymer with multiple hydroxy groups capable of engaging in hydrogen bonding that produces a rigid environment that is resistant to oxygen permeation. We thus investigated TPA-CO2H in this host matrix at 1 wt% doping in drop-cast PVA films. The low doping concentration ensures that the observed emission occurs only from monomolecular species. Powder X-ray diffraction (PXRD) measurements of the drop-cast 1 wt% doped film in PVA (Figure ) show no strong diffraction peaks, indicating that the film is largely amorphous and similar to that of a pristine dropcast PVA film. As schematically shown in Figure , TPA-CO2H can engage in multiple hydrogen bonds with PVA, which should suppress the conformational and vibrational motions of the guest. TPA-CO2H showed blue luminescence under 365 nm UV excitation at 298 K. Upon ceasing the 365 nm excitation, the afterglow of TPA-CO2H was observed to last for over 5 s (Figure , inset). At 298 K, the steady-state PL spectrum shows a structured blue emission with a lPL at 468 nm, alongside a highenergy shoulder peak at 424 nm (Figure ), whose tPL detected at 424 nm and 468 nm are nearly identical at 2.3 and 3.0 ns, respectively (Figure ). Time-gated emission studies reveal that the lower energy band at 468 nm is phosphorescence, which aligns with that recorded in frozen 2-MeTHF glass and Zeonex films (Figures and). The tPh recorded at 298 K is 275 ms (Figure ).