2-(Alkoxycarbonylmethylidene)-4-aryl-5- (dialkylamino)thiophen-3(2H)-ones were synthesized by condensation of N,N-(dialkyl)warylthioacetamides with dialkyl acetylenedicarboxylates. Intermediate substituted vinylic sulfides were isolated. When heated or in the presence of an acid or a base, they undergo cyclization into thiophenes.