In the title compound, [Zn2(C8H4O4)Cl2(C19H12N4)2(H2O)2] or [Zn2(BDC)Cl2(L)2(H2O)2] (where BDC is benzene-1,4-dicarboxylate and L is 2-phenyl-1H-1,3,7,8,-tetraaza-cyclopenta[l]phenanthrene), the two ZnII atoms are bridged by the BDC ligand to form a dinuclear compound in which each ZnII atom is five-coordinated by two N atoms from one L ligand, one chloride ion, and two O atoms, one from the BDC and one from the water molecule. The molecule is centrosymmetric. Neighbouring dinuclear complexes interact through π–π contacts to form stacks, leading to a two-dimensional supramolecular structure.