The hydrothermal reaction of Cd(OAc)2·2H2O, 4,4'-bpy and cyclohexane-1,2,4,5-tetracarboxylic acid (H4L) yields a three-dimensional (3D) coordination porous framework [Cd2LI(4,4'-bpy)1.5(H2O)2]n·2nH2O, which was characterized by single-crystal X-ray diffraction (MoKα radiation, λ = 0.71073 (A)), elemental analysis and IR. This complex crystallizes in the monoclinic system, space group C2/c with a = 25.951(3), b = 11.6618(12), c = 20.046(2) (A), β=114.863(2)°, V= 5504.4(10) (A)3, Z= 8, Dc= 1.900 g/cm3, Mr = 787.30, μ = 1.615 mm-1, F(000) =3128, the final R= 0.0978 and wR= 0.1780. The structure of the complex is a 3D coordination Cd-carboxylate framework consisting of 1D hexagonal channels along the c-axis filled with the bridging 4,4'-bpy ligands. The 4,4'-bpy ligands with two kinds of conformations are located alternately in the channels through coordination and hydrogen interactions to support the whole porous framework, in which the conformation-flexible cyclohexane-1,2,4,5-tetracarboxylate ligand adopts the Ⅰ (e,a,a,e) conformation and acts as a pentadentate ligand to connect five Cd(Ⅱ) atoms via the carboxylate groups in different coordination modes.