The effect of capping agents (Piperazine, Polyvinylpyrrolidone and triton X) on the functional properties of CdS nanostructures have investigated. SEM analysis revealed the formation of different morphologies of CdS nanostructures in the presence of different capping agents. Surface passivation of CdS with polyvinylpyrrolidone and piperazine lead to the formation of CdS nanorods, whereas capping with triton X resulted in the formation of CdS clusters. XRD studies revealed the formation of cubic phase and hexagonal phase with polyvinylpyrrolidone, triton X and piperazine, respectively. Absorption and emission studies revealed that the capping agents play an important role in passivation of the dangling bonds on the nanoparticle surface and greatly influence the optical properties. (C) 2016 Elsevier B.V. All rights reserved.