Electrochemical oxidation of methyl (±)-4, 7-dihydro-3-isobutyl-6-methyl-4-(3-nitrophenyl)thieno[2, 3-b]pyridine-5-carboxylate (1), a new dihydropyridine calcium blocker, in both methanol and acetonitrile was investigated by cyclic voltammetry, macroscale controlled potential electrolysis (CPE), in situ electron spin resonance (ESR) and ultraviolet-visible spectral studies. CPE of 1 in methanol at the potential of the first anodic peak on cyclic voltammetry gave four final products, the corresponding pyridine (2, yield, 73.9%), the 2-methoxy-substituted derivative of 2 (3, 11.9%), the 2, 2'-dimer (4, 7.9%) and the 2, 5'-dimer (5, 5.8%), while in acetonitrile, CPE of 1 gave 2 (12.2%), 4 (85.3%) and 5(1.2%). It is suggested that the initial step is a one-electron oxidation of 1 to give the radical cations based on the results of in situ ESR. A possible mechanism of the electrode reactions of 1, which involves one-electron oxidation followed by deprotonation, radical coupling, substitution and further oxidation, is proposed.