N -Acetyl- L -Leucine(NAL), a single crystal with dimensions up to 9 × 4 × 2 mm 3 was grown. The grown crystal is associated with noncentrosymmetric space group P2 1 2 1 2 1 and crystallizes in orthorhombic crystal system. This grown crystal is characterized by powder XRD analysis. Further, various molecular vibrations in the material was confirmed by FTIR and FT-Raman spectrum. Lower cut off of NAL single crystal was found to be 298 nm. The melting point of the crystalline powder sample of NAL was found to be180°Cand decomposes at 308 °C. In photoluminescence studies the emission of the crystals was observed at 305 nm. SHG efficiency of NAL was around 4.3 times that of KDP, as determined by the Kurtz-Perry powder technique. Quantum chemical calculations of the NAL molecules were performed using the Gaussian 09 software program. The energy value of HOMO–LUMO orbital’s was also investigated using Frontier Molecular Orbital analysis. The molecular nonlinear properties, molecular electrostatic potential map, and Mulliken charge analysis were all performed and discussed in detail.