Glycine and its related compounds play a prominent role in the field of nonlinear optical studies and of fibre optical communication. In the present work, glycine sodium nitrate (GSN) crystal was grown using the method of slow evaporation method. The GSN crystal belongs to space group Cc in the monoclinic system. Using the FTIR spectrophotometer, the different functional groups have been qualitatively identified. A UV–Vis–NIR spectroscopy was used to record the optical absorption spectra, and the optical energy bandgap of GSN crystal is reported. The SHG conversion efficiency of GSN is determined by Kurtz and Perry technique. The Z-scan experiment was conducted to analyze GSN crystal for third-order NLO behavior and it is used to calculate the values of the nonlinear absorption coefficient, nonlinear refractive index, and third-order nonlinear susceptibility. Third-generation harmonic studies reveal that GSN is an excellent material useful in the fabrication of NLO devices due to its nonlinear response characteristics. The thermal stability of the grown crystal was determined through TG/DTA examination. Also photoconductivity studies confirm the negative photoconductive behavior of GSN and I–V characteristics measurement that have been carried out. The dielectric loss is significantly low and this supports defect-free growth of the crystal. These properties of GSN make it a good candidate in the fabrication of NLO devices. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.