catena-Poly[[[tetra-aqua-manganese(II)]-μ-4,4'-bipyridine] bis-(3-hydroxy-cinnamate) dihydrate].

The title compound, {[Mn(C(10)H(8)N(2))(H(2)O)(4)](C(9)H(7)O(3))(2)·2H(2)O}(n), was obtained by the hydro-thermal reaction of manganese chloride with mixed 3-hydroxy-lcinnamic acid (H(2)L) and 4,4'-bipyridine (4,4'-bipy) ligands. The structure contains [Mn(C(10)H(8)N(2))(H(2)O)(4)](2+) cations with the Mn(II) atoms lying on a centres of inversion and bridged into a linear chain along the a axis by 4,4'-bipy ligands, surrounded by HL(-) anions and uncoordinated water mol-ecules. Extensive O-H⋯O hydrogen-bonding and weak π-π inter-actions [centroid-centroid distance = 3.7572  (3) Å] between the constituents lead to the formation of a three-dimensional supra-molecular network.