The crystallisation of 5-hydroxyisophthalic acid with divalent Mn or with Mn or Zn and either 2,2-bipyridine (2,2-bipy) or pyridine-2-(1H-pyrazol-3-yl) gave solids of composition [Mn(C 8 H 4 O 5 )(H 2 O) 3 ].2H 2 O (1), [Mn(C 8 H 4 O 5 )(2,2'-bipy)].H 2 O (2), [Mn 2 (C 8 H 4 O 5 ) 2 (C 8 H 7 N 3 ) 2 ].H 2 O (3) and [Zn(C 8 H 4 O 5 )(2,2'-bipy)] (4). Each compound has 1D co-ordinative chains that are connected by hydrogen bonds. Compounds 2-4 contain M 2 C 2 O 4 rings with pseudo-chair geometries. The Mn atoms in 2 are coupled antiferromagnetically.