Poly(3-dodecylthiophene) (P3DDT) and poly(3-decylthiophene) (P3DT) with high contents of head-to-tail linkages (86 and 85%, respectively) were synthesized in high yields by a facile oxidative polymerization with ferric chloride in chloroform at room temperature. We believe that the low concentration and ultraslow addition of monomers to ferric chloride contributed to the high regio-regularity. Differential scanning calorimetry thermograms indicated that the formed polymers consisted of crystalline, quasiordered, and disordered phases, which is a common feature of highly regioregular polymers. We prepared conductive fabrics with specific resistance of 30 and 100 Omega/sq by impregnating polyamide fabrics in a chloroform solution of P3DDT and P3DT, respectively. (C) 2004 Wiley Periodicals, Inc.