Dynamic measurements of changes in composition and conformation during adsorption of tetradecylmethyl viologen (C14MV) on a gold electrode were made using spectroscopic ellipsometry. Film thickness measurements indicated that a monolayer is initially formed in which the viologen species is in the upright extended position and that conversion to a tilted conformation occurs during equilibration to the final monolayer film. Subsequent reduction of the film as electrode potential was scanned from -0.2 to -0.9 V resulted in linear growth to a multilayer film in-which dications (C14MV2+) were reduced to radical (C14MV.+) and neutral (C14MV0) species. A gradual increase of the film charge-to-thickness ratio and of the film index of refraction during reduction indicated densification of the deposit. The pattern in the variation of film extinction coefficient with electrode potential indicated that radical dimers were the dominant species in the potential range corresponding to the first reduction step. During the reverse potential scan, the radical film detached due to faster reoxidation of the layers adjacent to the electrode surface.