Ethyl 3-cyano-4,6-diphenyl-2-pyridylthioacetate (<i>II</i>) yielded with hydrazine hydrate hydrazides <i>III, IV</i> that both proved to be versatile compounds for the synthesis of new heterocyclic derivatives. Thus the thieno[2,3-<i>b</i>pyridine derivatives <i>Xa - Xd</i> and <i>XIIa - XIId</i> were obtained