A two-fold penetration coordination polymer [Cu(bpy)(OH)]_n (1) (bpy＝4,4'-bipyridyl) has been synthesized through hydrothermal reaction and structurally characterized by single crystal X-ray diffraction method. Crystal data: tetragonal, space group I41/acd, a＝1.41802(6) nm, b＝1.41802(6) nm, c＝3.8568(3) nm, β＝90.00°, V＝7.7552(7) nm³, Z＝32, S＝1.074, final R indices [I＞2σ(I)] R₁＝0.0345, wR₂＝0.0767, for all reflections R₁＝0.0566, wR₂＝0.0867. In addition, the results of elemental analysis, IR and thermogravimetric analysis were presented.

Key words: hydrothermal reaction, two-fold penetration, coordination polymer, crystal structure