A new Zn(II) coordination polymer, namely, [Zn(pbta)(0.5)(bpa)]center dot 2H(2)O (1) [H(4)pbta = 5,5 '-phenylenebis(methylene)-1,1 '-3,3 '-(benzene-tetra-carboxyl c acid, bpa = 1,2-bis- (4-pyridyl)ethane]. The complex 1 has been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared spectra (IR), thermogravimetric analysis, UV-vis spectra, powder X-ray diffraction and X-ray single crystal diffraction. The complex 1 is formed by stacking of the 2D windows, and the 3-fold interpenetrated 3D network by hydrogen bonds between the coordinated water molecules and adjacent carboxylate oxygen atoms. In addition, the photocatalytic activities of complex 1 for decomposition of methylene blue (MB) under UV light have been investigated.