In the title compound, [Co(2)(C(7)H(2)N(2)O(7))(2)(C(19)H(12)N(4))(2)(H(2)O)(2)], the Co(II) atom is six-coordinated by two N atoms from a 2-phenyl-1H-1,3,7,8,-tetraaza-cyclo-penta-[l]phenanthrene (L) ligand, three O atoms from two 3,5-dinitro-2-oxidobenzoate (3,5-dinitro-salicylate or DNSA) ligands and one O atom from a water mol-ecule in a distorted octa-hedral geometry. The Co(II) atoms are bridged by two carboxyl-ate O atoms from two DNSA ligands, forming a centrosymmetric dinuclear structure. Neighbouring dinuclear units inter-act with each other through two types of π-π inter-actions between the L ligands [shortest centroid-centroid distance = 3.646 (3) Å] and between the L and DNSA ligands [shortest atom-to-centroid distance = 3.794 (3) Å]. N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds are observed, which lead to a three-dimensional structure.