Slow evaporation solution growth technique was employed to grow an optical single crystals of L-Threonine using water as solvent. It crystalizes in an orthorhombic system with space group P212121 was confirmed by single crystal X-ray diffraction. FT-IR spectral analysis verified the various functional groups present in the grown crystal. Optical characteristics were evaluated using UV-Vis-NIR analysis, it was observed with an optical band gap of 5.04 eV and the cut-off wavelength at 232 nm. The Urbach energy of the grown crystal was analysed and it appears to be minimum, which indicates that the L-Threonine has good crystallinity and Steepness parameter, Electron-phonon interaction energy were estimated. Optical properties such as extinction coefficient, optical conductivity and refractive index were measured in terms of photon energy and wavelength. Photoluminescence analysis of the material reveals great structural perfection of L-Threonine, confirms the emission of blue fluorescence. The laser damage threshold value was tested and it was calculated as 50.85 GW/cm2 for 1064nm wavelength of Nd:YAG laser radiation. The dielectric permittivity (ε՛) as a function of frequency was measured. The electronic polarizability (α) of the title crystal was calculated. Second Harmonic Generation (SHG) was tested by Kurtz-Perry powder technique and efficiency compared to standard KDP. This result indicates that the material has various NLO, photonic and optoelectronic device applications