Communication: CuInS2 (CIS) films for solar energy applications are typically made by rapid thermal sintering of the elements on a molybdenum-coated glass substrate. The photovoltaic cell is then completed by adding a CdS buffer layer and an Al/ZnO transparent electrode, all in all an expensive process. A low-cost colloidal route to nanocrystalline ZnO/CIS bilayers on indium tin oxide (ITO) glass is presented here, together with the optical and electrical characterization of the films. The concentrated coating colloids with size-quantized CIS particles that were developed for the film deposition are described.