The potentiostatic anodic oxidation of thin coats of poly(N-vinylcarbazole) on platinum electrodes, which produces electrically conductive polymers, is shown to involve cross-linking of the polymer chains through the oxidation of up to 50% of the carbazole moieties in the coat, followed by rapid dimerisation of the resulting pentant carbazole cation radicals; in turn, is followed by a further reversible 2-electron oxidation of the resulting dimeric carbazole entity.