Tungsten dioxo complex WO 2(C 9H 6NO) 2 was obtained via the low temperature solid-state reaction of(NH 4) 2WS 4, 8-hydroxyquinoline(8-hq) and(CH 3) 4NI, and it was characterized by means of elemental analyses, IR spectroscopy and X-ray diffraction analysis. The crystal of the title compound belongs to monoclinic, space group C2/c, with the crystal cell parameters: a=1.3316(3) nm, b=0.94444(19) nm, c=1.3485(3) nm, β=109.66(3)°, V=1.5970(6) nm 3, Z=6. The title compound possesses a supramolecular structure formed through hydrogen bonds and π-π stacking interactions. The third-order non-linear optical(NLO) properties of the title compound were also investigated. The third-order non-linear absorption coefficient α 2 and refractive index n 2 are 0.85×10 -11 m/W -1 and -1.5×10 -19 m 2/W, respectively. The third-order non-linear susceptibility χ (3) is 3.03×10 -13 esu for 3.8×10 -5 mol/L sample concentration. Tungsten dioxo complex WO 2 (C 9H 6NO) 2 was obtained via the low temperature solid-state reaction of (NH 4) 2WS 4, 8-hydroxyquinoline (8-hq) and of elemental analyzes, IR spectroscopy and X-ray diffraction analysis. The crystal of the title compound belongs to monoclinic space group C2 / c with the crystal cell parameters: a = 1.3316 (3) nm, b = 0.94444 , c = 1.3485 (3) nm, β = 109.66 (3) °, V = 1.5970 (6) nm 3, Z = 6 The title compound possesses a supramolecular structure formed by hydrogen bonds and π-π stacking interactions. -order non-linear optical (NLO) properties of the title compound were also investigated. The third-order non-linear absorption coefficient α 2 and refractive index n 2 are 0.85 × 10 -11 m / W -1 and -1.5 × 10 -19 m 2 / W, respectively. The third-order non-linear susceptibility χ (3) is 3.03 × 10 -13 esu for 3.8 × 10 -5 mol / L sample concentration.