Nickel(II) complex viz. bis(4′-chloro-2,2′:6′,2″-terpyridyl)nickel(II)chloride dihydrate, [Ni(Cltpy)2]Cl2·2H2O where Cltpy is a tridentate ligand was synthesized under mild conditions by conventional method. The octahedral geometry of nickel(II) complex was revealed by single crystal X-ray diffraction (SCXRD) studies. The synthesized Ni(II) complex was characterized by Fourier transform-infrared (FT-IR), elemental analysis, scanning electron microscope (SEM), thermal analysis (TG-DTA), photoluminescence (PL) and diffuse reflectance (DR) spectra. A prominent peak at 630 nm was recorded in the DR spectrum and the band gap energy of 2.38 eV was resulted in accordance with Kubelka-Munk (K-M) theory. The photoluminescent spectra of the synthesized nickel(II) complex displayed the emission of blue green light. The commission internationale de l’eclairage (CIE) coordinates (0.2641, 0.3722) were obtained from its CIE graph.