An intense red-green photoluminescence (PL) emission was observed, at room temperature, in a CdS@ZnS core-shell system. The PL intensity emission of CdS@ZnS core-shell was strongly superior from that observed in individual CdS and ZnS nanoparticles. In this sense, we reported a comprehensive experimental and theoretical study of the optical behavior of CdS and ZnS nanoparticles (NPs), and CdS@ZnS core-shell system in the light the structural order-disorder conception. We also propose a model were the core and shell interface leads to favorable condition that triggers PL emission in CdS@ZnS core-shell. (C) 2012 Elsevier B. V. All rights reserved.