In the title polymer, [Co(3)(C(6)H(8)O(4))(3)(C(19)H(12)N(4))(2)](n), two adipate dianions (C(6)H(8)O(4) (2-)) occupy general positions and two are situated on different inversion centres. The two on general positions bind through their four O atoms to five 2-phenyl-1H-1,3,7,8-tetra-azacyclo-penta-[l]phenanthrene-chelated Co(II) ions, whereas the two on special positions bind to only four. Of the three Co atoms, two are chelated by N-heterocycles; the third is bonded to six O atoms. The bonding mode of the dianion gives rise to a three-dimensional network structure; the network is further consolidated by N-H⋯O hydrogen bonds.