The synthesis and dialkyl abstraction chemistry as well as the unusual cocatalytic characteristics in metallocene-mediated polymerization of two distinctive borane and aluminate cocatalysts tris(2,2＇,2"-nonafluorobiphenyl)borane (PBB) and triphenyl carbenium tris(2,2＇,2"-nonafluorobiphenyl)fluoroaluminate, (Ph(3)C(+)PBA(-)) are reported. Reaction of PBB with Cp＇2ThMe2 (Cp＇ = eta(5)-C5Me5), CGCZrMe(2) (CGC = Me2-Si(eta(5)-Me4C5)(＇BuN)), and Cp＇MMe3 (M = Zr, Hf) cleanly affords base-free cationic complexes Cp＇2ThMe+MePBB- (1), CGCZrMe(+)MePBB(-) (5), and Cp＇MMe2+MePBB-(M = Zr, 7; Hf, 8). in case of CGCTiMe(2) and dimethyl zirconocenes, mu-methyl dinuclear cationic complexes [(CGeTiMe)(2)(mu-Me)](+) MePBB- (6) and [(L2ZrMe)(2)(mu-Me)]+MePBB- (L = eta(5)-C5H5 (CP), 2; eta(5)-1,2-Me2C5H3 (CP＇＇), 3; Cp＇, 4; L-2 = Me2Si(Ind)(2), Ind = eta(5)-C9H6, 9; L-2 = Me2C(Flu)(Cp), Flu = eta(5)-C13H8, 10) are formed. A similar reaction with Ph3C+PBA- results in the corresponding complexes CGCZrCH(3)(+)PBA(-) (M = Zr, 19; Ti, 20) and L(2)ZrCH(3)(+)PBA(-) (L = Cp, 15b; Cp", 16; eta(5)-1,3-(SiMe2)(2)C5H3, 17; Cp＇, 18; L-2 = Me2Si(Ind)(2), 21; L-2 = Me2C(Flu)(Cp), 22). Two dinuclear complexes 3 and 13 ([Me2C(Flu)(Cp)Zr(C6F5)](2)(mu-F)+MeB(C6F5)(3)(-)) derived from borane PBB and B(C6F5)(3), respectively, and three other PBA(-)-based monomeric complexes 14 (Ph(3)C(+)PBA(-)), 19, and 21 have been characterized by X-ray diffraction, and these determinations allow detailed analysis of the ion pairing in the solid state.