The reaction of bis(difluoroborondimethylglyoximato)nickel(II) and iodomethane with piperidine in acetone yields the deep-red, diamagnetic N,N-dimethylpiperidinium iodobis(difluoroborondimethylglyoximato)(nickelate(II) salt. The salt C15H28B2F4IN5O4Ni, crystallises in the monoclinic space group P21/c with dimensions a = 9.885(5), b = 19.042(6), c = 13.156(4) Å, β = 103.4(1)° and Z = 4. The structure was refined to R = 0.077 for 1684 photographic reflexions using least-squares calculations. The structure consists of discrete N,N-dimethylpiperidinium and iodobis(difluoroborondimethylglyoximato)nickelate(II) ions. In the anion the macrocycle encompasses the base of a square-based pyramid [average NiN 1.87(1) Å] with the nickel atom being displaced 0.19 Å from the N4-basal plane towards the apical iodine atom [NiI 2.842(2) Å]. Both glyoxime fragments of the macrocycle are closely planar with a dihedral angle between their planes of 8°. The axial fluorine atoms are in a cis-configuration. The piperidine ring of the cation adopts a chair conformation.