AbstractThe syntheses of benzo‐fused benzo[2, 1‐b:3, 4‐b′]dithiophenes1and benzo[2, 1‐b:3, 4‐b′:5, 6‐c″]trithiophenes2are described. The treatment of easily available 3, 3′‐bis(phenylethynyl)‐2, 2′‐bithiophene derivatives5aand6(viaPdII‐catalyzed alkynylation of the corresponding 3, 3′‐dibromo‐2, 2′‐bithiophenes; seeScheme 1) with chlorotris‐(triphenylphosphine)rhodium(I) yields the corresponding cyclic rhodium complexes7(Scheme 2) which smoothly react with acetylenes and sulfur