The 1:1 adduct of benzimidazole with bis(difluoroborondimethylglyoximato)nickel(II) is monoclinic, space group C2/c, a = 10.108(3), b = 20.450(6), c = 19.235(6) Å, β = 92.5(1)°, Z = 8. The structure was refined to R = 0.078 for 2504 photographic reflexions. The structure consists of discrete [Ni(dmg-BF2)2]2 dimer units, which have space group imposed 2(C2) symmetry, and benzimidazole molecules. The benzimidazole molecules are hydrogen-bonded to each other forming chains parallel to c that are incorporated in sheets centred about y = 0 and 1 2. The [Ni(dmg-BF2)2]2 dimer units are sandwiched between the sheets of benzimidazole molecules such that there are π-π interactions between the dmg fragments of the macrocyles and the benzimidazole rings. The Ni atoms are coordinated to four N atoms of a closely planar macrocycle [average NiN 1.848(6) Å, NNiN 83.0(3) and 97.0(3)°]. The Ni⋯Ni separation is 3.358(2) Å.