The [ML₂]⁺ [M = Co, L = Cp (η-C₅H₅), Cp* (η-C₅Me₅) or Ind (η-C₉H₇); M = Fe, L = Cp*] salts of the complex anions [Pt(C₆F₅)₄]²⁻, [Pt(C₆Cl₅)₄]²⁻, [Pt(C₆Cl₅)₄]⁻ and [PtCl₂(C₆Cl₅)₂]²⁻ were synthesised by solution phase stoichiometric reactions of the [NBuⁿ₄]⁺ salt of the anion with either a [BF₄]⁻ or [PF₆]⁻ salt of the appropriate organometallic cation. The crystal structures of 12 salts have been determined: [CoCp₂]₂[Pt(C₆F₅)₄] 1, [CoCp₂]₂[Pt(C₆Cl₅)₄]·Et₂O·Me₂CO 2, [CoCp₂][Pt(C₆Cl₅)₄] 3, [FeCp*₂]₂[Pt(C₆F₅)₄]·2CH₂Cl₂5, [FeCp*₂]₂[Pt(C₆Cl₅)₄]·2CH₂Cl₂6, [FeCp*₂][Pt(C₆Cl₅)₄] 7, [FeCp*₂]₂[PtCl₂(C₆Cl₅)₂]·MeCN 8, [CoCp*₂]₂[Pt(C₆F₅)₄]·2CH₂Cl₂9, [CoCp*₂]₂[Pt(C₆Cl₅)₄] 10, [CoCp*₂][Pt(C₆Cl₅)₄] 11, [CoInd₂]₂[Pt(C₆F₅)₄]·2MeCN 13, [CoInd₂]₂[Pt(C₆Cl₅)₄]·2Me₂CO 14. All of these structures show aromatic interactions between Cp (or Cp*) and perhalophenyl groups, as well as weak C–H⋯X interactions. Comparison between the structures of 3 and 11 shows the effect of cation size on the crystal structure. Both structures appear dominated by the larger [Pt(C₆Cl₅)₄]⁻ anions, with the metallocenium cations sandwiched between the perchlorophenyl rings. The structures containing [CoInd₂]⁺ cations (13 and 14) show π⋯π interactions between the extended π-systems of the indenyl ligands. The perchloro structures show larger solvent-occupied volumes and lower symmetry anions (approximately D₄vs.D_4h) than their fluoro analogues. The less symmetric [PtCl₂(C₆Cl₅)₂]²⁻ dianions of 8 also form π⋯π interactions, with the [FeCp*₂]⁺ cations sandwiched between two perchlorophenyl rings. The crystal structures of 5, 6 and 9 are each solvated by dichloromethane, with the solvent occupying notably different volumes in the structures of 5cf.6, and 5cf.9.