Single crystals of L-Leucinium Oxalate (LLO), an organic nonlinear optical (NLO) material have been successfully grown by slow solvent evaporation technique. The grown crystal was characterized by single crystal X-ray diffraction analysis. The optical properties of the grown crystals have been investigated by using UV-Vis-NIR spectrum. The thermal stability of the grown crystal has been investigated using thermo gravimetric analysis. The field dependence of dark and photo current of LLO were reported. The response of dielectric constant in the frequency region of 50 Hz to 5 MHz has been investigated. The second harmonic generation (SHG) in the sample was confirmed and compared with KDP by Kurtz powder technique.
