Ethyl-, and butylviologens were prepared by the Menschutkin reaction of 4,4 0 -dipyridyl and 1,2-dibromoethane and 1,4-dibromobutane. Elemental analysis and 1 H-NMR spectra showed that products consisted of symmetrical and asymmetrical substituted dipyridyls. Electrochemical reduction of these compounds in KBr and HCl solutions has been studied by the voltammetry method. The reduction process proceeds through several electrochemical and protonation steps, depending on the viologen structure and pH of the solution. The process results in a film formation on the electrode surface. The film is partly electroactive in the KBr solution, but completely passive in HCl. Reaction schemes have been proposed to explain this phenomenon.