When dpktch was reacted with ZnCl 2 in refluxing acetonitrile in air [ZnCl 2 ( 3 -dpktch)] was isolated in good yield. Infrared spectra suggest weaker binding of dpktch in [ZnCl 2 ( 3 -dpktch)] than in [CdCl 2 ( 3 -dpktch)]. 1 H-NMR studies in non-aqueous media show that [ZnCl 2 ( 3 -dpktch)] is sensitive to changes in its environment and exchanges its amide proton. Electronic absorption spectral measurements confirmed the sensitivity of [ZnCl 2 ( 3 -dpktch)] to changes in its surroundings and show inter-conversion between two intra-ligand-charge-transfer transitions (ILCT) at 330 AE 2 nm and 404 AE 2 associated with [ZnCl 2 ( 3 -dpktch)] and its conjugate base. Thermo-optical measurements in non-aqueous dmf and dmso show facile interconversion between [ZnCl 2 ( 3 -dpktch)] and its conjugate base, respectively. Also, it is shown that protonation of dmf by [ZnCl 2 ( 3 -dpktch)] is exothermic (standard enthalpy of protonation ÁH ¼ À40.7 AE 1.8 kJ mol À1 ), but endothermic for dmso (ÁH ¼ þ8.3 AE 1.5 kJ mol À1 ). Chemical stimuli in concentrations as low as 5.0 Â 10 À7 M can be detected and determined using [ZnCl 2 ( 3 -dpktch)] in non-aqueous media. X-ray crystallographic studies on a monoclinic, P2 1 /n single crystal of [ZnCl 2 ( 3 -dpktch)] confirmed the N,N,O-coordination of dpktch and revealed interdigitated units of [ZnCl 2 ( 3 -dpktch)] connected via a web of hydrogen bonds.