AbstractThe diazotization of various substituted naphthylamines has been found to be catalysed by the nucleophiles Cl−, Br−, SCN−and thiourea due to the formation of the corresponding nitrosyl salts. The rate controlling steps depend on the concentration of catalyst, with respect to which the order of the reaction varies between 1 and 0. The theoretical rate constants deduced from the proposed reaction mechanism are discussed in terms of the basicity of the amines and the nucleophilicity of the catalysts. The reaction rate's dependence on ionic strength and acidity in the absence of catalysts is also reported and disc