A neoteric organic third order nonlinear optical material 8-hydroxyquinolinium 2-chloro-5nitrobenzoate dihydrate (8HQ2C5N) was grown by slow cooling technique using ethanol: water (1:1) mixed solvent. The calculated low value of average etch pit solidity (4.12 x 10(3) cm(-2)) indicated that the title crystal contain less defects. From the single crystal X-ray diffraction data, it was endowed that 8HQ2C5N crystal belongs to the monoclinic system with centrosymmetric space group P2(1)/c and the cell parameters values, a = 9.6546 (4) angstrom, b = 7.1637(3) angstrom, c = 24.3606 (12) angstrom, alpha = gamma = 90 degrees,beta = 92.458(2)degrees and volume = 1683.29(13) angstrom(3). The FT-IR and FT -Raman spectrum were used to affirm the functional group of the title compound. The chemical structure of 8HQ2C5N was scrutinized by C-13 and H-1 NMR spectral analysis and thermal stability through the differential scanning calorimetry study. Using optical studies the lower cut-off wavelength and optical band gap of 8HQ2C5N were found to be 364 nm and 3.17 eV respectively. Using the single oscillator model suggested by Wemple Didomenico, the oscillator energy (E-o), the dispersion energy (E-d) and static dielectric constant (epsilon(o)) were estimated. The third -order susceptibility were determined as Im chi((3)) = 2.51 x 10(-5) esu and Re chi((3)) = 4.46 x 10(-7) esu. The theoretical third -order nonlinear optical susceptibility chi((3)) was calculated and the results were compared with experimental value. Photoluminescence spectrum of 8HQ2C5N crystal showed the yellow emission. The crystal had the single shot laser damage threshold of 5.562 GW/cm(2). Microhardness measurement showed that 8HQ2C5N belongs to a soft material category. (C) 2017 Elsevier B.V. All rights reserved.