The optically good quality single crystals of thiourea crystal grown in presence of ammonium acetate have been grown by slow evaporation solution growth technique. The single crystal X-ray diffraction and FTIR have been studied for grown crystal. The UV-Vis transmittance spectrum has been recorded in the range of 200-900 nm. Theoretical calculations have been carried out to determine the linear optical constants such as extinction coefficient and refractive index. The analysis of third order non-linear optical properties like non-linear absorption coefficient (b), non-linear refractive index (n2) and susceptibility (3) have been calculated using Z-scan technique. The dielectric and mechanical strength of doped crystals have been investigated and results are discussed