Excited-state properties of three different pyrazine derivatives 4−6 were probed by emission and transient absorption spectroscopy. They display emission maxima at 464 (4), 417 (5), and 515 nm (6) that are red-shifted with respect to their strong UV ground-state absorption and formed with overall quantum yields (Φ) of 0.156, 0.22, and 0.13, respectively. Once photoexcited, these triplet excited pyrazines undergo rapid intermolecular energy transfer to a monofunctionalized fullerene derivative (7) with bimolecular rate constants ranging from 3.64 × 109 M-1 s-1 (6) to 1.1 × 1010 M-1 s-1 (4). The product of these bimolecular energy-transfer reactions is in all cases the fullerene triplet excited state. Functionalization of pristine C60 with the investigated pyrazine derivatives promotes the UV−vis absorption characteristics and, in turn, improves the light-harvesting efficiency of the resulting dyads 1−3 relative to pristine C60. Photoexcitation of the pyrazine moieties in dyads 1−3 leads to the formation of...