C-F bond cleavage by transient phosphorus(III)-based dications [RP(C(PPh3)(2))](2+) (4a(2+), R = Ph; 4b(2+), R = 4-F-Ph) is reported. These dications were generated by reaction of the corresponding monocationic precursors with excess Na[BAr4Cl]. Evidence for the existence of transient dicationic species was obtained by trapping the dication 4a(2+) with PMe3. According to theoretical analysis, the low-lying lowest unoccupied molecular orbitals of these species were responsible for the observed activation of C-F bonds.