Abstract: A straightforward synthesis of substituted polythiophene-fused-3-sulfolenes from the readily prepared methyl 3-hydroxy-4,6-dihydrothieno[3,4-b]thiophene-2-carboxylate will be presented. Upon thermolysis in the presence of N-phenylmaleimide, these new substrates serve as precursors of reactive polythiophene o-quinodimethanes to give the corresponding Diels-Alder adducts in high yields.