Reactions of the C 60 cations C 60 •+, C 60 2+ and C 60 •3+ have been investigated with C 2H 2 and C 2H 4 in the gas phase using the Selected-Ion Flow Tube (SIFT) technique at 295±2 K and 0.35±0.02 Torr of helium. Although C 60 •+ was found to be unreactive (k < 1×10 −12 cm 3 molecule −1 s −1), and C 60 2+ reacted only slowly (k ≤ 2×10 −12 cm 3 molecule −1 s −1) by adduct formation, C 60 •3+ reacted rapidly with C 2H 2 by adduct formation (k = 6.6×10 −11 cm 3 molecule −1 s −1) and with C 2H 4 by adduct formation (30%) and electron transfer (70%) (k = 1.7×10 −9 cm 3 molecule −1 s −1). C 58 •3+, which was present as an impurity ion, was observed to react 10 times faster than C 60 •3+ with C 2H 2, k = 6.0×10 −10 cm 3 molecule −1 s −1 and this was attributed to a greater sp 3 character of the reacting C site. Higher-order addition reactions were observed with C 60 •3+ and C 58 •3+ and these were interpreted as the first example of cation-induced “ball-and-chain” polymerization by triply-charged fullerene cations. Mechanisms have been proposed for this polymerization without and with an intramolecular hydride shift in the derivatized fullerene cation. Also, C 60C 2H 4 •3+ was observed to undergo proton transfer with C 2H 4 and this is the first example of such a reaction with a triply-charged C 60 derivative.