A novel nickel complex [Ni₂L₂Phen₃]·3H₂O (HL = 3-hydroxy-2-methylquioline-4-carboxylic acid) has been synthesized by a hydrothermal approach and is structurally determined by single-crystal X-ray diffraction. The title complex crystallizes in triclinic space group P . Crystal data for the title complex: C₅₈H₄₄N₈Ni₂O₉, M_r = 1108.35, a = 11.8648(4), b = 12.7369(4), c = 17.0728(5) Å, α = 97.694(3), β = 96.702(2), γ = 99.566(3)°, V = 2495.66(14) ų, Z = 2, T = 293(2) K, D_c = 1.475 g/cm³, μ(MoKα) = 0.824 mm^–1, F(000) = 1140, R = 0.0757, wR = 0.2129 and GOF = 1.017. The nickel ions are surrounded by five oxygen and six nitrogen atoms to yield two slightly distorted octahedral geometries. Solid-state photoluminescence spectrum reveals that it shows blue purple emission. Solid-state UV/Vis diffuse reflectance spectroscopy exhibits that it has an optical band gap of 1.702 eV.