The reactions of nickelocene with pyrazoles in benzene solution have resulted in the isolation of either dimeric compounds, [CpNi(μ-pz′)]2, (room temperature conditions) or trimetallic complexes, [CpNi(μ-pz″)2]2Ni, (elevated temperature conditions). Both dimeric and trimetallic species were obtained as red crystalline materials and X-ray structural investigations are reported for representative samples of each type. Structural features are interpreted and compared with similar, previously reported, nickel pyrazolate structures. Crystals of [CpNi(3,5-diMepz)]2 (C20H24N4Ni2), 1, are orthorhombic, a = 15.204(1), b = 17.967(2), c = 6.9786(9) Å, Z = 4, space group Ama2; those of [CpNi(4-NO2-3,5-diMepz)]2 (C20H22N6Ni2O2), 5, are orthorhombic, a = 17.145(3), b = 17.738(1), c = 7.006(1) Å, Z = 4, space group P212121; those of [CpNi(3,5-F6diMepz)]2 (C20H12F12N4Ni2), 6, are orthorhombic, a = 18.7134(8), b = 15.619(2), c = 7.7263(9) Å, Z = 4, space group Pnma; those of [CpNi(3,5-diMepz)2]2Ni (C30H38N8Ni3), 7, are triclinic, a = 10.078(2), b = 16.134(2), c = 9.992(1) Å, α = 91.586(10)°, β = 111.050(9)°, γ = 86.95(1)°, Z = 2, space group [Formula: see text]; and those of [CpNi(4-Cl-3,5-diMepz)2]2Ni (C30H34Cl4N8Ni3), 10, are monoclinic, a = 10.2201(7), b = 16.174(1), c = 10.7207(9) Å, β = 108.193(5)°, Z = 2, space group P21/a. The structures were solved by direct (dimetallic species) or Patterson (trimetallic complexes) methods and were refined by full-matrix least-squares procedures to R = 0.035, 0.032, 0.058, 0.032, and 0.033 (Rw = 0.021, 0.026, 0.053, 0.028, and 0.032) for 1157, 1894, 1642, 4499, and 2113 reflections with I ≥ 3σ(F2), respectively. Keywords: crystal structures, nickel, nickelocene, pyrazolates, cyclopentadienyl.