Tetra-2-thienyl- and Tetrakis(5,2′-bithiophene-2-yl)thiophenes and Selenophenes.

Heating a mixture of di-2-thienylacetylene (1) and elemental selenium in benzene at 220-225°C for 9 h in a stainless steel autoclave affords tetra-2-thienylselenophene (2b) in 65% yield. In similar ways, heating a mixture of bis(5,2'-bithiophene-2-yl)acetylene (3) and elemental sulfur or selenium gives tetrakis-(5,2'-bithiophene-2-yl) thiophene (4a) or selenophene (4b), respectively, in satisfactory yields