catena-Poly[[(2,9-dimethyl-1,10-phenanthroline-κN,N')cobalt(II)]-μ-malonato-κO,O:O,O].

In the title compound, [Co(C(3)H(2)O(4))(C(14)H(12)N(2))](n), the Co(II) ion is in a distorted octa-hedral coordination being chelated by a 2,9-dimethyl-1,10-phenanthroline mol-ecule (dmphen) and two carboxyl-ate groups of two malonate ligands The malonate ligand acts in a bridging mode, forming coordination chains along [100]. π-π stacking inter-actions between dmphen ligands [inter-planar distances = 3.414 (4) and 3.