4-Bromomethylidene-2-imino(phenylimino, acetylimino)-1,3-thiazolidine hydrobromides and 4-bromomethylidene-2-acetylimino-1,3-thiazolidine are synthesized by the reaction of thiourea, N-phenylthiourea, N,N'-diphenylthiourea and N-acetylthiourea with 1,3-dibromopropyne in glacial acetic acid, absolute methanol, acetonitrile at 20 degrees C or upon heating (60 degrees C).