Poly[(acetato-κO,O')aqua-(μ(4)-1H-benzimidazole-5,6-dicarboxyl-ato-κN:O,O:O,O:O)praseodymium(III)].

In the title complex, [Pr(C(9)H(4)N(2)O(4))(C(2)H(3)O(2))(H(2)O)](n), the Pr(III) ion is coordinated by five O atoms and one N atom from four benzimidazole-5,6-dicarboxyl-ate ligands, two O atoms from an acetate ligand and one water mol-ecule, giving a tricapped trigonal-prismatic geometry. The benzimidazole-5,6-dicarboxyl-ate and acetate ligands connect the Pr(III) ions, forming a layer in the ac plane; the layers are further linked by N-H⋯O and O-H⋯O hydrogen bonding and π-π stacking inter-actions between neighboring pyridine rings [the centroid-centroid distance is 3.467†(1)†à ], assembling a three-dimensional supra-molecular network. The acetate methyl group is disordered over two positions with site-occupancy factors of 0.75 and 0.25.