In the present study, a generic method for the modification of optical band gap of CdS nanostructures material over a wide spectral range due to Pb doping and formation of Cd(1-x)Pb(x)S nanoparticles and its size confinement is reported. The composite investigated in this study was grown by thermal decomposition of metal xanthates and lead concentration was varied to obtain different lead doping. This is a direct decomposition one pot synthesis route that avoids use of toxic phosphine and injection of chemicals during the reaction. The prepared nanoparticles were characterized by XRD, SEM, EDX, and HRTEM. The optical absorption properties of the Cd(1-x)Pb(x)S nanostructures were investigated by UV-visible spectroscopy. Cd(1-x)Pb(x)S nanoparticles showed tuning of the band gap from 2.7 eV to 0.7 eV.