Two novel coordination polymers, [Cu(H2L)(bipy)(H2O)(2)]center dot H2O (1) and [Ni-2(H2L)(bipy)(2.5)(H2O)(6)]center dot(H2L)center dot 7H(2)O (2) with the V-shaped diphosphonate ligand (2,4,6-trimethyl-1,3-phenylene) bis(methylene) diphosphonic acid (H4L) were synthesized via hydrothermal reactions in the presence of auxiliary ligand 4,4'-bipyridine. Their structures were determined by single-crystal X-ray diffraction and further characterized by elemental analysis, infrared spectroscopy (IR), and thermogravimetric analysis (TGA). Compound 1 crystallizes in the Pnma space group and compound 2 crystallizes in the P2(1)2(1)2 space group. They display square-grid layer and bilayer two-dimensional network, respectively.