Despite trifluoromethylfullerene Cs-C70(CF3)8 has a multitude of available reaction sites, [2+1] cycloaddition of CX2 moieties (X=F and p-MeOC6H4) proceeds regioselectively at a particular [5,6]-bond. Depending on the nature of X, the resulting derivative can be either [5,6]-open (i.e., the said CC bond is cleaved) or [5,6]-closed, and this structural detail, seemingly insignificant for a molecule that large, brings about a remarkable 0.6eV difference in the electron affinity, as revealed by electrochemical studies. Synthesis, structural and electrochemical elucidation of the C70(CF3)8(CX2) compounds are discussed, as well as electrochemically promoted switching of the electronic properties based on disruption of the conjugated 62π-electron system into the isolated 32 and 28π-electron fragments upon closing the [5,6]-bond.