TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Methods: The reacting is carried out any solvent in addition to indene or substituted indene. The method comprises reacting greater than or equal to 2 fullerenes, subjecting the two fullerenes to a separation step, isolating indene-fullerene derivative containing greater than or equal to 4, preferably greater than or equal to 5 indenes or substituted indenes per fullerene, removing indene or substituted indene, precipitating indene-derivatized fullerene, obtaining extract to yield a residual reaction product, and subjecting the residual reaction product to further reaction. The reacting step provides mixture of indene-fullerene reaction products. Preferred Components: The fullerene is 60C and/or 70C fullerene. The primary reaction product is bis-, tris-, tetra-, penta-, or hexa-substituted indene fullerene derivative. The any additional solvent is less than 20, preferably less than 5 volume % (vol.%) with respect to the indene and/or substituted indene. The indene, and/or substituted indene is present (at the start of the reaction) at greater than or equal to 300, preferably greater than or equal to 500 molar. The reaction product comprises product(s) which can be isolated in yields of greater than or equal to 60% with respect to the unreacted fullerene and fullerene reaction product. The first ring is optionally substituted with substituent(s). The substituent(s) is hydroxyl, acyl(amino), acyloxy, aminoacyl, carboxyl, carboxyl esters, cyano, halo, nitro, and/or optionally substituted alkyl, alkenyl, alkynyl, amino, aryl, aryloxy, (cyclo)alkoxy, thiol(alkyl), thiocycloalkyl, thioheterocyclic, cycloalkyl, heteroaryl, heterocyclic, heteroaryloxy, and/or heterocyclyloxy. The fullerene comprises only carbon or derivative group(s) bonded to fullerene besides R. The composition comprises fullerene derivative ( greater than or equal to 95, preferably greater than or equal to 99 pts. wt.). Preferred Parameters: The reaction is carried out at greater than or equal to 150, preferably greater than or equal to 180 and greater than or equal to 1.2, preferably greater than or equal to 5 atm for less than or equal to 48, preferably less than or equal to 24 hours. EXAMPLE - Fullerene 60C was dissolved in o-dichlorobenzene at 6 mg/ml. Indene (12-fold molar excess relative to fullerene 60C) was added and the resulting mixture was refluxed overnight. The solvent was evaporated under reduced pressure and precipitation occurred after adding ethanol. The resulting solid was dried, re-dissolved in toluene, and then analyzed by using high-pressure liquid chromatography using Cosmosil Buckyprep analytical column on Agilent 100 series instrument with wavelength detector at 330 nm. Toluene (1 ml/minute) was used for elution. Peaks at elution time of 5.4 minute and group of peak of 4 minute were attributed to 60C-indene mono- and bis-adducts, respectively. The presence of several peaks with very close elution times of 4 minute was consistent in the presence of isomers. Elution times were shorter than that of unfunctionalized 60C was observed. Multiple additions were found to lead to further decrease of elution times. A pentabromobenzyl-functionalized silica phase was used for purification using flash chromatography. Pure toluene and toluene/cyclohexane mixture were used for purification. HPLC analysis of collected fractions showed purities 98.5% for 60C-indene monoadduct and 95% for mixture of different bis-adducts.