Thiourea potassium hydrogen phthalate (TKHP), a semiorganic nonlinear optical single crystal is grown by slow evaporation solution growth technique at room temperature. FUR and NMR spectral studies of the grown crystal confirm the chemical composition and their corresponding functional groups. UV -visible NIR spectral study confirms the transmission band of 100% in the range 200-900 nm with enhanced lower cutoff wavelength. The Single crystal XRD reveals that the grown crystal is an orthorhombic system. Thermal stability of TKHP was found to be 305.1 degrees C. The second harmonic generation (SHG) efficiency of TKHP is observed by the Kurtz powder technique. (C) 2016 Elsevier B.V. All rights reserved.