Poly[diaqua-(μ(4)-2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ato-κ(4)O(1):O(2):O(4):O(5))(μ(2)-2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ato-κ(2)O(1):O(4))bis-(1,10-phenanthroline-κ(2)N,N')dimanganese(II)].

In the title compound, [Mn(2)(C(10)H(4)O(8))(2)(C(12)H(8)N(2))(2)(H(2)O)(2)](n), the Mn(2+) ion has a slightly distorted octa-hedral N(2)O(4) coordination geometry being coordinated by one aqua O atom, two N atoms of the chelating 1,10-phenanthroline ligand and three carboxyl O atoms from three 2,5-dicarb-oxy-benzene-1,4-dicarboxyl-ate (H(2)btec(2-)) ligands. The H(2)btec(2-) anion exhibits two different coordination modes, viz. μ(2) and μ(4). Both of the H(2)btec(2-) anions are located on special positions (inversion centers). The μ(4)-anion bridges adjacent Mn(II) atoms, forming a chain along the a axis. Adjacent chains are further bridged by μ(2)-anions, resulting in a two-dimensional layered polymer parallel to (011). In the crystal, extensive carb-oxy-carboxyl-ate O-H⋯O and water-carboxyl-ate O-H⋯O inter-actions lead to the formation of a three-dimensional supra-molecular network.