In the title compound, [Zn(C(6)H(2)N(2)O(4))(C(18)H(10)N(4))(H(2)O)](n) or [Zn(PZDC)(DPPZ)(H(2)O)](n) (where DPPZ is dipyrido[3,2-a:2',3'-c]phenazine and H(2)PZDC is pyrazine-2,3-dicarboxylic acid), the Zn atom is six-coordinated in a slightly distorted octa-hedral coordination geometry by three N atoms from one DPPZ ligand and one PZDC(2-) dianion, three O atoms from two different PZDC(2-) ligands and one water mol-ecule. Each PZDC(2-) dianion serves as a spacer, connecting adjacent metal atoms into a polymeric chain structure parallel to the b axis. The chain motif is consolidated into a three-dimensional supra-molecular network by O-H⋯O and O-H⋯N hydrogen bonds and π-π aromatic stacking inter-actions involving adjacent DPPZ ligands and PZDC(2-) dianions with centroid-centroid separations of 3.522 (6) and 3.732 (8) Å, respectively.