Abstract A one pot synthesis gives methyl-5, 6, 7, 8-tetrahydrodinaphtho [1, 2-b: 2′, 1′-d] thiophenes (7) from methyl-1, 2, 3, 4-tetrahydronaphthalen-1-ones (1) by bromination and sufurization. Tetrahydro compounds 7 have been dehydrogenated to corresponding dinaphtho [b, d] thiophenes 8. Proofs for the constitutions are nmr data of 7, 8 and the independent synthesis of one compound 8. A reaction mechanism with 1, 4-dithiine ...