The reaction of lauroyl isothiocyanate with ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate gave ethyl 2-(3-dodecanoylthioureido)-4,5,6,7-tetrahydrobenzo[b]thiophene-3-carboxylate 3. Compound 3 could serve as a main building block in synthesis of the target heterocyclic systems like thieno[2,3-d]-pyrimidine, thieno[2′,3′:4,5]pyrimido[1,2-a][1,3,5]triazine, thieno[2,3-d]-1,3-thiazine and 1,2,4-triazole systems attached to the lauryl group. The structures of the synthesized target heterocyclic compounds were confirmed by microanalytical and spectral data. The antimicrobial activity of some of the synthesized compounds was tested.