We report a systematic study of structural, optical, and magnetic measurements on Zn(0.9)Cd(0.1)S:yCo films in the concentration range of 0.005 <= y <= 0.05 M using pulsed laser deposition technique. Structure, composition analysis, and optical measurements revealed that Cobalt is incorporated into the lattice, as Co(2+) substituting Zn(2+) ions, forming a solid solution with cubic structure instead of Cobalt precipitates. Low temperature magnetization measurements reveal a paramagnetic behavior. UV-vis measurements showed a red shift with respect to undoped sample in the energy band gap with increasing Cobalt concentration. Photoluminescence measurements shows similar to 300 times increase in intensity by Cobalt doping in Zn(0.9)Cd(0.1)S matrix. (C) 2011 Elsevier B.V. All rights reserved.