The asymmetric unit of the title complex, [Ni(C10H8N2)(H2O)4]SO4, consists of a complex [Ni(bipy)(H2O)4]2+ cation (bipy = 2,2′-bipyridine) and a non-coordinating [SO4]2− anion. The NiII atom is six-coordinated in a distorted octa­hedral geometry defined by the two N atoms of the bipy ligand and four water O atoms. The crystal structure contains extensive classical O—H⋯O hydrogen bonds, which link the ions into a two-dimensional array in the ab plane. Layers are connected into a three-dimensional supra­molecular structure by C—H⋯O inter­actions.

The racemic title compound, [Cu2(C7H8NO2)2Cl2], is composed of dinuclear mol­ecules in which meth­oxy(pyridin-2-yl)methano­late ligands bridge two symmetry-related CuII ions. Each CuII ion is coordinated in a square-planar geometry by one Cl atom, the N and O atoms of the bidentate ligand and the bridging O atom of the centrosymmetrically related bidentate ligand. The separation between the two CuII atoms is 3.005 (1) Å. In the crystal, non-classical C—H⋯O hydrogen bonds, weak π–π stacking [centroid–centroid distance = 4.073 (1) Å] and weak electrostatic Cu⋯Cl inter­actions [3.023 (1) Å] link the dinuclear mol­ecules into chains running parallel to the b axis. These chains are further connected by weak C—H⋯Cl hydrogen bonds directed approximately along the a axis, forming a three-dimensional supra­molecular network.