To interrogate the correlation between the number of hydrogen bonds between the guest and host to the RTP intensity we conducted a similar photophysical investigation using both TPA and TPA-CO2Me at 1 wt% doping in PVA. As anticipated, TPA-CO2Me, a hydrogen-bond acceptor, exhibits RTP (Figure ), though the RTP is much less intensive and shorter-lived (FPh= 9% and tPh= 150 ms, Figure ) than that of TPA-CO2H due ostensibly to weaker hydrogen bonding interactions. By contrast, no afterglow was observed at 298 K in the 1 wt% doped film of TPA in PVA as TPA cannot generate hydrogen bonds with the host matrix (Figure ). These results clearly demonstrate the importance of hydrogen bonding between guest and host to suppress non-radiative decay, leading to a turn-on of the RTP. We next investigated the photophysical properties of TPA-CO2H doped in boric acid as a matrix.