4-Imidazolylsulfonamides and 4-imidazolylsulfonylimidazoles are useful as plasticizers. These compounds are obtained by reaction of 4-imidazolesulfonyl chloride with an amine, such as imidazole. 4-Imidazolesulfonyl chloride itself is useful as a reactant with textile materials such as cotton to increase flame resistance.