A metalorganic NaHC2O4·H2O single crystal was successfully grown by slow evaporation method. The grown crystal was exposed to single crystal X-ray diffraction which confirms that the crystal belongs to triclinic crystal system with P1¯ space group having unit cell parameters a = 6.53 Å, b = 6.71 Å, c = 5.72 Å and α = 75°, β = 85.06°, γ = 70.31°. The presence of functional groups, bonding between the organic ligand and the metal atoms were identified through FT-IR spectral studies. The UV–vis–NIR study revealed that the transparency of the grown crystal was about 60% in the entire visible region and the cut-off wavelength was observed at 295 nm. The TG/DTA studies reveal that the metalorganic complex is thermally stable upto 125 °C. The thermodynamic parameters of various decomposition point for different temperatures were also calculated. Vickers microhardness test was carried out on grown crystal to study its mechanical stability. The frequency dependent dielectric constant and dielectric loss were analysed. The electrical relaxation mechanism has been studied using AC conductivity. Another interesting feature of this centrosymmetry sodium hydrogen oxalate hydrate crystal shows an SHG active signal and efficiency is almost equivalent to that of KDP. © 2017 Elsevier B.V.