The title complex, {[Cu-2(C8H4O4)(2)(C3H4N2)(4)(H2O)]center dot H2O}(n), is a three-dimensional polymer formed through bridging by phthalate dianions of two different Cu-II cations and a network of O(N)-H center dot center dot center dot O hydrogen bonds. The Cu-O and Cu-N interaction distances are in the ranges 2.0020 (16)-2.4835 (17) and 1.968 (2)-1.9855 (19) angstrom, respectively. The structure is composed of alternating polymer chains parallel to the c axis, with a shortest Cu center dot center dot center dot Cu distance of 6.3000 (5) angstrom.