The electrochemical oxidation of 3-methylthiophene, thiophene and 2',5'- dibtyloxy-3-rnphenylthiophene have been studied using plalinium, glassy carbon and gold electrodesrnin acetonitrile. Lithium perchlorate served as supporting electrolyte in all experiments.rnThe oxidation of 3-methyl thiophene at different concentration was carried out on Pt,rnGC and Au electrodes using de cyclic voltammetry. As the concentration increases, arnpreadsorption peak was noted in all electrodes. It was seen that the PI electrode isrnmore sensitive to the adsorpt ion of the product (radicals). The oxidation of 3-rnmethylthiophene was also performed under potentiastatic conditions. It was observedrnthat the current response decays with time at a rotating electrode. This shows thatrndiffusion is not a rate determining step in the oxidation of 3-methylthiophene.rnThe limiting charge passed on stationary and rotating Pt electrode was evaluated onrnthe primary oxidation of 4.2 mmol L-1 3-methylthiophene on Pt electrode. Attempts werernmade to compare the charge passed with the theoretically charge expected from thernmonola/ er coverage of the electrode surface.rnThe diffusion coefficient of ferrocene was determined on stationary Pt electrode. Thisrnvalue was compared with that of 3-methylthiophene and thiophene. The higher valuernof the diffusion coefficient of thiophene and 3-methylthiophene was due to a smallerrnmolecular radius.rnIn the electrochemical oxidation of 2',5'-dibutyloxy-3-phenylthiophene at least threernanodic oxidation peaks were observed in both DC and AC cyclic voltammetry. The firstrnpeak potential occurred around 1.05 V, the second at 1.47 Vand the third aroundrn1.91 V.