We describe the synthesis of [o-Ph₂P(O)(C₆H₄)SbPh₃]⁺ ([2]⁺), an intramolecularly base-stabilized stibonium Lewis acid which was obtained by reaction of [o-Ph₂P(C₆H₄)SbPh₃]⁺ with NOBF₄. This cation reacts with fluoride anions to afford the corresponding fluorostiborane o-Ph₂P(O)(C₆H₄)SbFPh₃, the structure of which indicates a strengthening of the PO → Sb interaction. When deployed in fluoride-containing POPC unilamellar vesicles, [2]⁺ behaves as a potent fluoride anion transporter whose activity greatly exceeds that of [Ph₄Sb]⁺.