Densely covered (ET)X-2 thin films (ET = bis-ethylenedithio-tetrathiafulvalene, X = counter-anion) can be formed by selective electrodeposition on gold electrodes (see Figure). The insulating (ET)X-2 films are converted to (ET)(2)X conductive thin films through a novel conproportionation reaction. This procedure opens up the possibility to prepare patterned conductive and superconductive charge-transfer salt thin films.