Recognizing that the acceptors contain Lewis basic nitrogen atoms of differing number and strength and we decided to assess the potential of these compounds to act as selective optical sensors of Lewis acids. Although TADF luminophores have shown great potential as sensors, such as for oxygen, as temperature probes, and for acid-base sensing. There is to date no report on the use of TADF luminophores for Lewis acid sensing. We first investigated the optical sensing responses of TPAPyBP (1.3´10 -4 M) towards different metal ions. There is a quenching of the PL intensity of TPAPyBP at 550 nm with varying degrees of efficiency upon addition of excess of various metal salts (NaCl, NiCl2, Ni(OAc)2, CuI, Cu(OAc)2, CoCl2, CuCl, CuCl2, ZnCl2, SnCl2, Zn(BF4)2, FeCl3, and AlCl3) in an ethanol/toluene(1/99, v/v) solvent mixture Figure and). Remarkably, the emission responses upon addition of ZnCl2 and SnCl2 are particularly distinct, as in both cases there are the emergence of new, strong emission bands at around 680 nm (Figure and). However, it is noteworthy that only the addition of ZnCl2 to the TPAPyBP toluene solution resulted in a distinct intense red emission. As shown in Figure , new, strong absorption bands were observed for ZnCl2, SnCl2, Zn(BF4)2, FeCl3 and AlCl3.