AbstractEleven anilino‐vinyl, ‐propenyl and ‐butenyl quaternary salts have been examined for fungitoxicity. The structure‐activity correlation was similar to that found for carbocyanines. The activity of the salts resided in the cations. Benzoxazolium derivatives were found to be more active than benzthiazolium or benzselenazolium derivatives. Phenylation of the benzoxazolium salts enhanced their activity. Alkyl substituents enhanced the activity of the benzthiazoliu