Single crystal of 4Sodium substituted 1,4 but-2-ene-di-oic crystals has been grown by slow evaporation method. Single crystal x-ray diffraction analysis shows that it belong to Triclinic system. The presence of functional groups was confirmed by Fourier Transform Infrared Spectroscopy. Optical behavior has been studied by UV-Vis analysis and found that there is no absorption in the entire visible region. The NLO efficiency of the crystal has been confirmed by the Kurtz Perry method using Nd-YAG laser.