Herein, we report the synthesis of conducting poly (terthiophene)s using a side chain precursor polymer approach. Random copolymers were prepared by ring opening metathesis polymerization of two norbomylene monomers, one containing a pendant terthiophene group and the other containing a pendant acetate group. Solid-state oxidative conversion of the terthiophene units was used to produce conductive polymers. Oxidative solid-state conversion was successful for copolymers containing as little as 1 mol % of terthiophene comonomer. The electrical and optical properties of CPs were studied as a function of the amount of electroactive moiety, terthiophene (3T), present in the copolymer. The CPs were found to have conductivity varying between 10(-1) and 10(-4) S/cm depending on the precursor copolymer compositions. The Cps obtained from all precursors had no significant difference in their energy gaps and showed blue to orange color transitions when switching from the oxidized to the neutral states, respectively. The absorbance intensity at 426 nm for poly(3T) from the precursors fits the Beer-Lambert law corresponding to the range of initial 3T content in the precursor copolymer composition (from 1 to 100 mol %). (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 756-763, 2010