Br-terminated polystyrenes of controlled molar masses and low polydispersities prepared by atom transfer radical polymerization (ATRP) can be converted to macroradicals using an appropriate catalytic complex (CuBr/bipyridine/100 degreesC). The addition of this macroradicals PSdegrees to 6-6 bonds of C-60 follows a specific atom transfer radical addition mechanism that favors the grafting of even number of chains onto the fullerene core. This peculiar mechanism, resulting from the properties of C-60, offers an easy synthetic route toward well-defined di- and tetra-adducts. In these adducts the disturbance of the electronic structure of the fullerene is kept at its minimum, as only one double bond needs to be opened on the C-60 to add two PS chains and only two double bonds are converted to single bonds in the tetra-adduct. (C) 2004 Wiley Periodicals, Inc.