Three new metal-organic coordination complexes have been prepared and their crystal structures determined: [Ni(oda)(H₂O)₃]·1.5H₂O, [Ni(oda)(phen)(H₂O)]·1.5H₂O and [Ni(oda)(terpy)]·2H₂O (oda=oxydiacetate, PHEN=1,10-phenanthroline, TERPY=2,2′:6′,2″ terpyridine). The oxydiacetate ligand is tridentate in these compounds, being hinged in the first and nearly planar in the other two. Hydrogen-bonding and π–π interaction is extensive in the solids.