cis-[(7R,14R)-5,5,7,12,12,14-Hexa-methyl-1,4,8,11-tetra-azacyclo-tetra-decane-κN](oxalato-κO,O')nickel(II) oxalic acid solvate.

Both mol-ecules of the title compound, [Ni(C(2)O(4))(C(16)H(36)N(4))]·C(2)H(2)O(4), are located on a crystallographic twofold rotation axis. The Ni(II) atom shows a distorted octa-hedral geometry. The crystal packing is stabilized by N-H⋯O and O-H⋯O hydrogen bonds.