AbstractHydrogen, as well as the halogen atom, at the 4 or 5 position in some 5‐ and 4‐nitroimidazoles were displaced by various nucleophiles such as the amino, cyano, hydroxy, and alkoxy groups. The greater reactivity of the departing group in the 4 position, which was regularly observed, is ascribed to the double activating effect of the azo and nitro groups. Cyanide ion in alcoholic solution reacted peculiarly with both 4‐ and 5‐nitroimidazoles givingo‐cyanoazoxyimidazoles as the only products. In some of the nucleophilic displacements at the 4 position of 5‐nitroimidazoles the formation of intermediate S̀‐complexe