The whole molecule of the title compound is generated by inversion symmetry; the central benzene ring being situated about a crystallographic inversion center. The aromatic ring of the julolidine moiety is inclined to the central benzene ring by 33.70 (12)°, and the conformation about the C=N bonds is E. There are two intramolecular O—H⋯N hydrogen bonds in the molecule, generating S(6) ring motifs.
In the title coordination polymer, [Co(C3H3O4)Cl(H2O)]n, the sixfold coordination environment of the CoII atom consists of two O atoms from a chelating hydrogen malonate anion (HMal−), one O atom originating from a μ2-bridging malonate ligand (HMal−), one O atom from a water molecule and two μ2-bridging Cl− atoms, connecting neighbouring Co2Cl4 motifs into a two-dimensional polymer extending parallel to (001). Interlayer O—H⋯O hydrogen bonds link the layers into a three-dimensional network.