We report here the use of sulfonated fullerene derivatives and dendrimers with multiple -(O)SO3H groups as protonic acid dopants for polyaniline emeraldine base (PANI-EB). While doping of PANI-EB films with the sulfonated dendrimers gives conductivities up to ca. 10 S/cm, the hydrogensulfated fullerenol-doped materials show metallic characteristics with room-temperature conductivities as high as 100 S/cm-about 6 orders of magnitude higher than the typical value for fullerene-doped conducting polymers. This, coupled with the anticipated photoinduced charge-transfer effects characteristic of fullerene C-60 and potential biomedical applications of dendrimers, could make these highly conducting materials useful in many advanced optoelectronic and/or biomedical devices.