Two new coordination polymers [Cd(4,4'-tmbpt)(HL)(H 2 O)] (1) and [Cu(4,4'-tmbpt)(HL)]•H 2 O (2) (H 3 L = 2'-carboxybiphenyl-4-ylmethylphosphonic and 4,4'-tmbpt = 1-((1H-1,2,4-triazol-1-yl)methyl)-3,5-bis(4-pyridyl)-1,2,4-triazole) have been synthesized hydrothermally. The two compounds have the same metal to ligand ratio, but different metal ions. As a result, the two compounds display different 2D layer structures, which is mainly caused by the different coordination numbers of