catena-Poly[[[diaqua-copper(II)]-bis-[μ-1,5-bis-(1H-imidazol-1-yl)pentane-κ(2) N (3):N (3')]] naphthalene-1,5-disulfonate].

In the title complex, {Cu(C11H16N4)2(H2O)2} n , the Cu(II) atom, lying on an inversion center, is six-coordinated by two water mol-ecules and four N atoms from four 1,5-bis-(1H-imidazol-1-yl)pentane (biim-5) ligands in a distorted octa-hedral geometry. Adjacent Cu(II) atoms are linked by two biim-5 ligands, forming a chain along [111]. Two atoms of the pentane group are disordered over two sets of sites, with an occupancy ratio of 0.554 (18):0.446 (18). Inter-molecular O-H⋯O hydrogen bonds link the chains and the centrosymmetric naphthalene-1,5-disulfonate anions into a layer structure parallel to (0-11).