Electrochemical polymerization of 1H,7H‐pyrrolo[2′,3′:4,5]‐thieno[3,2‐b]pyrrole and 4H‐dithieno[3,2‐b;2′,3′‐d]pyrrole

Electrochemical polymerization of 1H,7H‐pyrrolo[2′,3′:4,5]thieno[3,2‐b]pyrrole and 4H‐dithieno[3,2‐b;2′,3′‐d]pyrrole in CH3CN + 0,1 M p‐toluenesulfonate and tetraethylammonium perchlorate, respectively, yields polymers with a conductivity of ca. 5 S/cm. Electrochemistry and elemental analysis indicate the presence of 0,6‐0,7 anions per monomeric unit, while spectroelectrochemistry agrees with a polypyrrole structure for polypyrrolothienopyrrole and a polythiophene structure for polydithienopyrrole. The redox cycle for polypyrrolothienopyrrole (at −0,53 V vs. Ag/Ag+) is close to that of polypyrrole, while that of polydithienopyrrole (at 0,0 V) is intermediate between those of polythiophene and polypyrrole. N‐Alkylsubstituted dithienopyrroles produce soluble polymers with higher conductivity (40 S/cm) and the lowest band‐gap (1,7 eV) ever reported for a polythiophene‐like polymer.