The present investigation work shows the results of Cd1-XZnXS thin films (where X= 0.04, 0.08, 0.12, 0.16 and 0.2), obtained by total ammonia-free chemical bath processes. The reaction solutions were prepared with precursors of metallic salts as CdCl2 and ZnCl2 and replacing the ammonia with trisodic citrate (C6H5O7Na3) as complexing agent. The reaction solutions were stabilized with KOH to get alkaline solutions. As result of adding Zn, the as deposited films showed changes in their morphological, structural and optical properties. Moreover, additional changes were obtained when thermal treatments to 400°C under N2 environment were applied to the as deposited films. The agglomerates at the surface of the annealed films showed larger grain sizes compared to that of the as deposited films. Due to preferential orientation of the hexagonal wurtzite-type structure in the films, changes in the intensity in the (002), (100) and (101) peaks from x-ray diffraction analysis were observed. Finally, a reduction on the maximum energy band gap from 2.65 to 2.59 eV was obtained as effect of the annealing treatment to the films.