Chemical reactions of imidazole on metallic silver, copper, and mercury surfaces have been studied by infrared spectroscopy and surface enhanced Raman scattering. It was found that the interaction of imidazole with the metals at zero oxidation state yielded metal imidazolates which covered the metal surfaces as a passive thin layer. As shown by tight-binding extended Huckel molecular orbital calculations, the ease of the reaction suggests that the reactivity of imidazole is increased upon adsorption which involves electron transfer from the metal to imidazole antibonding orbitals and the weakening of the N-H bond in the imidazole molecule.