Lithium niobate (LN) is deposited on quartz substrate by sol-gel method. The solution is deposited at different molarity concentration and annealed at 500 degrees C. The LNs are analyzed by UV-visible and Photoleuminces. The results show when the concentration increases, the films crystallize to be more regular distribution of atoms and the energy band gap approaches 4 eV. Transmission spectra were taken in the wavelength range 400-1100 nm. Optical investigations of band gap, refractive index, extinction coefficient, dielectric constant and Urbach energy were also elaborated. (C) 2015 Elsevier Ltd. All rights reserved.