[en] In this paper, a facile spray pyrolysis technique was utilized to synthesize CoNi₂S₄ thin films. The influence of spray time on the structural, optical and electrical properties of the CoNi₂S₄ thin films was studied. The x-ray diffraction studies of the CoNi₂S₄ thin films illustrate that the films exhibit a polycrystalline nature with cubic structure. The values of the lattice strain ε, and the dislocation density δ, were decreased as the spray time increase while the grain size has reverse manner to lattice strain ε, and the dislocation density δ. The transmittance and reflectance spectra of the CoNi₂S₄ thin films were recorded in the wavelength range of (400–2500) nm to evaluate the optical parameters of the CoNi₂S₄ thin films. Optical absorption coefficient of CoNi₂S₄ thin films revealed a presence of a direct energy gap and the values of energy gap were decreased from 1.68 to 1.53 eV as the spray time increases from 15 min to 45 min. The nonlinear refractive index of the CoNi₂S₄ thin films was increased with increasing of the spray time. The CoNi₂S₄ thin films exhibit single activation energy and the activation energy was decreased as the spray time increased. (paper)