Monomesylhydrazide, 1-acetyl,2-mesylhydrazide, and sym-dimesylhydrazide were obtained by means of the Schotten–Baumann reaction. For comparison with these compounds the hydrazinium dimesylate, hydrazinium monomesylate, monomesylhydrazide mesylate, and monoacetylhydrazide mesylate were prepared. The preparation of dimesyldiimide by the action of metallic sodium on N,N-dichloromesylamide was attempted.