C-F bond cleavage by transient phosphorus(III)-based dications [RP(C(PPh3)2)]2+ (4a2+, R = Ph; 4b2+, 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 4a2+ 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. © 2015 American Chemical Society.