Two new coordination polymers, namely, [Co(mu-nip)(mu-bpe)] (n) and [Zn(mu-nip)(mu-bpe)](n) (2) (nip: 5-nitroisophthalate, bpe: 1,2-bis(4-pyridyl)ethane) were hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermal analysis. Moreover, atomically detailed simulation studies of complex 2 for CO2/CH4 adsorption and separation were performed. Complex 1 consists of two dimensional (2D) (4,4) grid networks with the point symbol of 4(4).6(2). Complex 2 exhibits a 3-fold interpenetrating 3D framework with 6(5).8-dmp topology. Thermal properties of the complexes showed that both complexes were stable over 320 C. Simulation studies demonstrated that complex 2 can separate CO2 from CH4 at low pressures at 273 K. (C) 2013 Elsevier Inc. All rights reserved.