A new 3d-4f heterometallic coordination polymer, [CuGd2(INAIP) 3(HCOO)(H2O)3]·3H2O (1), [H2INAIP = 5-(isonicotinamido)isophthalic acid] has been synthesized and characterized by single crystal X-ray diffraction analysis. The results of structural analyses show that 1 has a two-fold interpenetrated 3D coordination framework with a rare sqc27 topology. In addition, thermogravimetric and magnetic proper...