A novel porous lanthanide-organic coordination polymer, [Nd（H2O）（HnicO）（TP）]·2H2O （1） （H2nicO=2-hydroxynicotinic acid, TP= terephthalate）, was prepared under hydrothermal condition and characterized by single-crystal X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. Compound 1 exhibited a flexible coordination geometry of lanthanide ions, which possessed a three-dimensional （3D） open framework with one-dimensional （1D） channels containing lattice water molecules. This framework structure exhibited a high stability up to 330℃ after removing free water molecules. A homometallic supramolecular framework （Zn（HnicO）2（H2O）2 （2）） was obtained due to the competitive reaction between organic ligands, Nd3＋ and Zn2＋ ions. The results showed that on the basis of the soft-hard/acid-base principle the coordination selection between metal ions and organic ligands played an essential role in the smart construction of lanthanide architectures.
