The properties of chalcopyrite (CuInS2) semi-conductor nanoparticles make them attractive materials for use in next-generation photovoltaics. Traditional thermolysis methods of preparing CuInS2 from molecular single source precursors (SSPs) have inherit disadvantages involving non-uniform heating and long reaction times. Microwave irradiation methods have allowed us to increase the efficiency of preparation of these materials by providing increased uniformity of heating and shorter reaction times. We have also controlled nanoparticle growth by variation of thiolated capping ligand concentration as well as reaction temperatures and times. Preparation, characterization, and properties of our CuInS2 chalcopyrite nanoparticles synthesized by microwave irradiation will be discussed. Investigation of the photophysical properties of the colloidal nanoparticles were performed using techniques such as electronic absorption and luminescence emission spectroscopy. Qualitative nanoparticles sizes determined from the photoluminescence (PL) data, and compared to TEM characterization will also be presented.