The present work investigates the effect of precursor concentration (mc) on the structural, optical, morphological and electrical conductivity properties of In2S3 thin films grown on amorphous glass substrates by nebulized spray pyrolysis (NSP) technique. The mixed phase of cubic and tetragonal structure of In2S3 thin films at higher concentration has been observed by X-ray diffraction pattern. The reduced strain by increasing the precursor concentration increased the average crystallite from 17.8 to 28.9nm. The energy dispersive analysis by X-ray (EDAX) studies confirmed the presence of In and S. The transmittance, optical direct band gap energy, Urbach energy and skin depth of In2S3 films have been analyzed by optical absorption spectra. The better conductivity and mobility noticed at mc=0.15M are explained by carrier concentration and crystallite. Better optical and electrical conductivity behaviour of In2S3 thin film sample proposes for effective solar cell fabrication.