The title compound Cu 2Cl 2phen (phen=1,10 phenanthroline, C 12 H 8N 2) 1 was synthesized from CuCl 2·2H 2O, CuCl and phen by hydrothermal method and its structure was determined by single crystal X ray analysis. With phen, CuCl forms one dimensional chains, which comprise two zigzag chains based on fused Cu X units and connected via covalent bonds. The compound contains two crystallographically unique monovalent copper ions, Cu(1) and Cu(2). The Cu(1) atom in the tetrahedral site, is coordinated to two bridging Cl - and two N atoms in phen. The Cu(2) atom with a slightly distorted triangular planar geometry, is coordinated to three Cl -. The compound 1 was crystallized in monoclinic, space group P 2 1/ n with a = 0.37338(4) , b =1.9510(2), c =1.68008(19) nm, β =95.605(3)°, R =0.0458, and was characterized by elemental analysis, IR spectrum and TGA analysis. The title compound Cu 2 Cl 2 phen (phen = 1,10 phenanthroline, C 12 H 8N 2) 1 was synthesized from CuCl 2 · 2H 2O, CuCl and phen by hydrothermal method and its structure was determined by single crystal X ray analysis. With phen , CuZ forms one dimensional chains, which comprise two zigzag chains based on fused Cu X units and connected via covalent bonds. The compound contains two crystallographically unique unique copper ions, Cu (1) and Cu (2). The Cu in the tetrahedral site, is coordinated to two bridging Cl - and two N atoms in phen. The Cu (2) atom with a slightly distorted triangular planar geometry, is coordinated to three Cl -. The compound 1 was crystallized in monoclinic, space group (2), c = 1.68008 (19) nm, β = 95.605 (3) °, R = 0.0458, and was characterized by elemental analysis, IR spectrum and TGA analysis.