A semiorganic lithium para-nitrophenolate dihydrate (LiPNP·2H₂O) nonlinear optical crystal with a dimension of has been grown by slow evaporation method in a rapid growth period of 20 days by using ethanol as solvent. Powder X-ray diffraction studies revealed the crystal belong to monoclinic crystal system with space group of P2₁. The optical transmission study revealed a wider transparency with the lower cut-off wavelength of 457 nm and an optical bandgap of 2.91 eV. The emission properties, functional groups, and mechanical stability of the obtained crystal were determined by Photoluminescence, FTIR spectral analysis, and Vickers’s microhardness measurements. The electrical conductivity and thermal stability were examined through electrochemical impedance (EIS) and TG-DTA analysis. The Second harmonic generation efficiency (SHG) of the crystal was found to be 2.6 times greater than that of the standard KDP. Therefore, LiPNP·2H₂O crystal with high SHG efficiency could be a suitable candidate for nonlinear optical and optoelectronic device applications due to its optical, thermal, and mechanical properties.