Samples of CuInSe2 with a wide composition range were prepared by electrodeposition from Cu(II), In(III), and Se(IV) precursors. According to the preparation conditions, sample groups were defined and characterized for their structural, optical, and photovoltaic properties. A postthermal treatment was carried out in order to improve the quality of the as-deposited films. Strong correlations with the film composition are clearly evident with respect to the deposition conditions. Sample groups exhibit different properties, which are analyzed in terms of deviations from molecularity (Delta m) and stoichiometry (Delta s).