© 2016, National Institute of Optoelectronics. All rights reserved.The optical properties of CdS nanoparticles (NPs) are explored as a function of nanoparticle size and concentration. Nanocomposite (NC) thin films with semiconductor CdS nanoparticles formed in a polymer matrix using successive ionic layer adsorption and reaction (SILAR) technique showed very attractive optical properties due to quantum confinement effects. For bulk CdS materials, the absorption peaks can only be tuned in a narrow range. The nanostructure size and shape were characterized by scanning electron microscope (SEM), the optical properties were studied by UV-Vis spectroscopy, FT-IR and photoluminescence spectroscopy (PL).