In the present work, L-Cysteinium Sodium Nitrate Chloride (LCSNC) an organic nonlinear optical material has been synthesized by a slow evaporation method. The crystalline nature was confirmed by single crystals X-ray diffraction analysis. The UV-Vis transmittance spectrum shows that the crystal has a good optical transmittance in the entire visible region with lower cutoff wavelength 203 nm. The various functional groups and chemical compositions of the grown crystal have been derived from FTIR spectral analysis. Both dielectric constant and dielectric loss decrease with an increase in frequency. The SHG efficiency was measured by employing the powder Kurtz method.