The synthesis of a bipyridine ligand with a flexible spacer and a noncoordinating amine group N,N-(2-pyridyl)(4-pyridylmethyl)amine, L-2, and its coordination chemistry with cadmium have been investigated. Two-dimensional (2D) coordination polymers of L-2 with empirical formulas [Cd(L-2)(2)(ClO4)(2)](infinity), 1, or [Cd(L-2)(2)(NO3)(2)](infinity), 2, were prepared by hydro(solvo)thermal reactions of L-2 and Cd(ClO4)(2). 6H(2)O or Cd(NO3)(2). 4H(2)O in mixtures of water and ethanol, respectively. Single-crystal X-ray diffraction studies reveal that 1 and 2 have similar structures in which each L-2 ligand bridges two cadmium centers with both the 4-pyridyl and 2-pyridyl nitrogen atoms to result in 2D rhombohedral polymeric grids. The two rings of L-2 are essentially perpendicular to each other, likely to accommodate the coordination of both pyridyl nitrogen atoms to the Cd centers as well as the "intramolecular" hydrogen bonds between the amine group in the flexible spacer and the coordinated anion group. When the hydro(solvo)thermal reaction was carried out between L-2 and CdSO4. 6H(2)O, a 3D Cd coordination polymer [Cd-2(L-2)(4)(H2O)(2)(SO4)(2)](infinity), 3, resulted. Two distinct Cd centers reside in the asymmetric unit in 3. One Cd center coordinates to four 4-pyridyl nitrogen atoms of L2 ligands and two sulfate groups, while the other Cd center binds to two 2-pyridyl nitrogen atoms, two sulfate groups, and two water molecules. The two distinct cadmium centers are bridged by both L-2 ligands and sulfate groups to result in an unusual 3D polymeric structure. Crystal data for 1: monoclinic space group C2/c, a = 8.4931(6) Angstrom, b = 17.264(1) Angstrom, c = 16.699(1) Angstrom, beta = 99.517(6)degrees, V = 2559.4(1) Angstrom(3), Z = 4, R = 0.034, R-w = 0.039. Crystal data for 2: monoclinic space group C2/c, a = 8.6231(5) Angstrom, b = 17.288(1) Angstrom, c = 16.1675(7) Angstrom, beta = 94.730(2)degrees, V = 2401.9(1) Angstrom(3), Z = 4, R = 0.050, R-w = 0.058. Crystal data for 3: monoclinic, space group P2(1)/n, a = 11.7188(2) Angstrom, b = 15.7525(3) Angstrom, c = 12.8528(1) Angstrom, beta = 93.064(1)degrees, V = 2369.2(1) Angstrom(3), Z = 2, R = 0.042, R-w = 0.047.