Six new coordination polymers, [Eu(1,2-BDC)(1,2-HBDC)(phen)(H2O)](n) (1), [Eu-2(1,3-BDC)(3)(phen)(2)(H2O)(2)](n).4nH(2)O (2), [Eu(1,4-BDC)(3/2)(phen)(H2O)](n) (3), [Yb-2(1,2-BDC)(3)(phen)(H2O)(2)](n) . 3.5nH(2)O (4), [Yb-2(1,3-BDC)(3)(phen)(1/2)](n) (5), and [Yb-2(1+BDC)(3)(phen)(2)(H2O)](n) (6), were synthesized by hydrothermal reactions of lanthanide chlorides with three isomers of benzenedicarboxylic acid (H2BDC) and 1,10-phenanthroline (phen), and characterized by single-crystal X-ray diffraction. 1 has a 2-D herringbone architecture with a Z-shaped cavity. 2 and 5 have different 3-D networks, but both are formed by 1,3-BDC anions bridging metal centers (Eu or Yb) via carboxylate groups. 3 and 6 possess similar layer structures which are further constructed to form 3-D networks by hydrogen bonds and/or g-g aromatic interactions. 4 comprises 1-D chains that are further interlinked via hydrogen bonds, resulting in a 3-D network. In the three europium complexes, all the europium ions are eight-coordinated, while the coordination numbers of the ytterbium ions in other three-coordination polymers range from six to eight. Crystal data: for 1, monoclinic, space group P2(1)/c, with a = 12.565(6) Angstrom, b = 16.005(8) Angstrom, c = 12.891(6) Angstrom, beta = 102.173(8)degrees, and Z = 4; for 2, monoclinic, space group P2(1)/c(1) with a = 20.979(4) Angstrom, b = 11.5989(19) Angstrom, c = 20.810(3) Angstrom, beta = 110.391(3)degrees, and Z = 4; for 3, triclinic, space group P (1) over bar, with a = 10.331(5) Angstrom, b = 10.887(5) Angstrom, c = 11.404(5) Angstrom, alpha = 107.660(7)degrees, beta = 91.787(7)degrees, gamma = 112.946(6)degrees, and Z= 2; for 4, triclinic, space group of, with a = 11.517(5) Angstrom, b = 13.339(5) Angstrom, c = 13.595(6) Angstrom, alpha = 87.888(7)degrees, beta = 67.759(6)degrees, gamma = 68.070(6)degrees, and Z = 2; for 5, orthorhombic, space group C222(1), with a = 8.174(2) Angstrom, b = 24.497(7) Angstrom, c = 29.161(8) Angstrom, and Z = 8; for 6, triclinic, space group P (1) over bar, with a = 10.349(3) Angstrom, b = 11.052(3) Angstrom, c = 19.431(6) Angstrom, alpha = 105.464(4)degrees, beta = 91.300(5)degrees, gamma = 93.655(5)degrees, and Z = 2. The magnetic properties of 1 and 4 were investigated. The photophysical properties of 1 were also studied.