Third order nonlinear optical semi-organic potassium hydrogen maleate single crystal was grown by Sangaranarayanan-Ramasamy (SR) method. The formation of the bonds in the crystal was confirmed by FTIR analysis. Thermal properties were analyzed, and found that the grown crystal is thermally stable up to 196°C. The transparency (74%) was assessed from the UV-Vis studies. The photo-luminescence spectral study revealed yellow emission in the wavelength region 500-650nm. The surface laser damage threshold value of the grown crystal was measured by using Nd:YAG laser. Z-scan technique was employed to observe the third-order nonlinear optical property of the grown crystal.