Abstract: | Carbon—carbon bond‐forming polymerization of 2‐bromo‐3‐(3′,5′‐di‐t‐butyl‐4′‐methoxyphenyl)‐thiophene yields poly[3‐(3′,5′‐di‐t‐butyl‐4′‐methoxyphenyl)‐2,5‐thienylene] with regiospecific connectivity and a degree of polymerization of about six. Lewis‐acid‐moderated‐cleavage of the methoxy groups on the pendant phenyl group yield the corresponding polyphenolic polymer, which is oxidized under solution conditions to yield the title polyradical. Poly[3‐(3′,5′‐di‐t‐butyl‐4′‐oxyphenyl)‐2,5‐thienylene] exhibits a strong, persistent electron spin resonance spectrum and a UV–visible spectrum consistent with formation of the pendant phenoxyl spin‐bearing units. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 779–788, 1999 |