The reduction peak of a linear potential sweep voltammogram of 1,1′‐diheptyl‐4,4′‐dipyridinium dibromide in water, was found to be very steep with at a scan speed less than 0.1 V/sec. This behavior was discussed on the basis of a model consisting of a reversible electron transfer and a coupled chemical reaction in analogy with reversible metal deposition. With modified viologens similar results have been obtained. The role of the coupled chemical reaction was underlined by the observed Nernstian dependence on cation and/or anion concentrations of both first and second reduction peak potential. The observed anodic peak of the first reduction step differs from the peak expected from the dissolution of a bulk deposit.