Single crystals of glycine sodium nitrate (GSN), a semiorganic nonlinear optical material has been grown from solution by slow evaporation at ambient temperature. The solubility of GSN has been determined in water. Formation of the new crystal has been confirmed by powder XRD pattern and IR spectra. GSN crystallises in monoclinic system with cell parameters a = 14,323(4)Angstrom, b = 5.2575(8)Angstrom, c = 9.1156(14)Angstrom, beta = 119.030(18)degrees, space group Cc. The optical second harmonic generation conversion efficiency of GSN was determined using Kurtz powder technique and found to be two times that of KDP. (C) 2002 Published by Elsevier Science B.V.