The identity of the metal-organic framework formed by Mn(ii) and 4,4[prime or minute]-dicarboxy-2,2[prime or minute]-bipyridine (H(2)dcbp) depends upon the predominant solvent employed in the synthesis and yields the robust network isomers [[Mn(dcbp)][middle dot]1/2DMF](n), and [[Mn(dcbp)][middle dot]2H(2)O](n), which possess vastly different physical properties: irretrievably binds DMF, whereas reversibly binds water whilst retaining crystallinity.