Eight types of fulleropyrrolidine–imidazolium hybrids have been synthesized and their solubility determined in various types of organic solvents. The solvent solubility of fullerene derivatives depends on the alky side chain on the imidazolium ring; modification of solvent solubility of the fulleropyrrolidine–imidazolium hybrids has thus been accomplished by introduction of an appropriate alkyl group using imidazoyl moiety as the 'functional group ...