In this research, the effects of initial concentrations on the optical properties of Cadmium Selenide nanostructured thin layers synthesized by the chemical solution deposition method have been investigated. Experimental data showed that the initial concentration controlling during deposition has a remarkable role in the optical band gap energy and thin film configuration. It was found that thin film thicknesses increase with increasing of the initial concentrations so a sample with higher initial concentration degrades the dye pollutant in more effective in comparison with a sample of the low initial concentration. The methylene blue and condo red were used as a pollutant to estimate the photocatalytic action of the sample. The optical band gap for deposited thin films decreased from 3.52 eV to 1.86 eV also Urbach energy, equal to the values of the tail of localized states increase from 0.176 to 0.9 eV with increasing of the initial concentration.
