The title compound, [Ni(C8H12BN4)(C13H18BN6)] or Bp'Tp'Ni(II), where Bp' is (3,5-dimethylpyrazol-1-yl)dihydro(pyrazol-1-yl)borate and Tp' is bis(3,5-dimethylpyrazol-1-yl)hydro(pyrazol-1-yl)borate, contains a divalent Ni(II) centre bound by the chelating N atoms of the polysubstituted pyrazolylborate ligands. It is shown to lack a strong agostic B-H...Ni interaction, implying that the sixth coordination site is unoccupied in the solid state. This square-pyramidal complex is the only known crystal structure where the Ni(II) centre is pentacoordinated while bonded exclusively to pyrazolyl units. This is of interest with respect to electrochemical and catalytic properties.