The reaction of [Ni₂(ⁱPr₂Im)₄(COD)] 1a or [Ni(ⁱPr₂Im)₂(η²-C₂H₄)] 1b with different fluorinated arenes is reported. These reactions occur with a high chemo- and regioselectivity. In the case of polyfluorinated aromatics of the type C₆F₅X such as hexafluorobenzene (X = F) octafluorotoluene (X = CF₃), trimethyl(pentafluorophenyl)silane (X = SiMe₃), or decafluorobiphenyl (X = C₆F₅) the C−F activation regioselectively takes place at the C−F bond in the para position to the X group to afford the complexes trans-[Ni(ⁱPr₂Im)₂(F)(C₆F₅)] 2, trans-[Ni(ⁱPr₂Im)₂(F)(4-(CF₃)C₆F₄)] 3, trans-[Ni(ⁱPr₂Im)₂(F)(4-(C₆F₅)C₆F₄)] 4, and trans-[Ni(ⁱPr₂Im)₂(F)(4-(SiMe₃)C₆F₄)] 5. Complex 5 was structurally characterized by X-ray diffraction. The reaction of 1a with partially fluorinated aromatic substrates C₆H_xF_y leads to the products of a C−F activation trans-[Ni(ⁱPr₂Im)₂(F)(2-C₆FH₄)] 7, trans-[Ni(ⁱPr₂Im)₂(F)(3,5-C₆F₂H₃)] 8, trans-[Ni(ⁱPr₂Im)₂(F)(2,3-C₆F₂H₃)] 9a and trans-[Ni(ⁱPr₂Im)₂(F)(2,6-C₆F₂H₃)] 9b, trans-[Ni(ⁱPr₂Im)₂(F)(2,5-C₆F₂H₃)] 10, and trans-[Ni(ⁱPr₂Im)₂(F)(2,3,5,6- C₆F₄H)] 11. The reaction of 1a with octafluoronaphthalene yields exclusively trans-[Ni(ⁱPr₂Im)₂(F)(1,3,4,5,6,7,8-C₁₀F₇)] 6a, the product of an insertion into the C−F bond in the 2-position, whereas for the reaction of 1b with octafluoronaphthalene the two isomers trans-[Ni(ⁱPr₂Im)₂(F)(1,3,4,5,6,7,8-C₁₀F₇)] 6a and trans-[Ni(ⁱPr₂Im)₂(F)(2,3,4,5,6,7,8-C₁₀F₇)] 6b are formed in a ratio of 11:1. The reaction of 1a or of 1b with pentafluoropyridine at low temperatures affords trans-[Ni(ⁱPr₂Im)₂(F)(4-C₅NF₄)] 12a as the sole product, whereas the reaction of 1b performed at room temperature leads to the generation of trans-[Ni(ⁱPr₂Im)₂(F)(4-C₅NF₄)] 12a and trans-[Ni(ⁱPr₂Im)₂(F)(2-C₅NF₄)] 12b in a ratio of approximately 1:2. The detection of intermediates as well as kinetic studies gives some insight into the mechanistic details for the activation of an aromatic carbon−fluorine bond at the {Ni(ⁱPr₂Im)₂} complex fragment. The intermediates of the reaction of 1b with hexafluorobenzene and octafluoronaphthalene, [Ni(ⁱPr₂Im)₂(η²-C₆F₆)] 13 and [Ni(ⁱPr₂Im)₂(η²-C₁₀F₈)] 14, have been detected in solution. They convert into the C−F activation products. Complex 14 was structurally characterized by X-ray diffraction. The rates for the loss of 14 at different temperatures for the C−F activation of the coordinated naphthalene are first order and the estimated activation enthalpy ΔH^⧧ for this process was determined to be ΔH^⧧ = 116 ± 8 kJ mol⁻¹ (ΔS^⧧ = 37 ± 25 J K⁻¹ mol⁻¹). Furthermore, density functional theory calculations on the reaction of 1a with hexafluorobenzene, octafluoronaphthalene, octafluorotoluene, 1,2,4-trifluorobenzene, and 1,2,3-trifluorobenzene are presented.