A series of linearly linked perylenediimide (PDI) dimers and trimers were synthesized in which the PDI pi systems are nearly orthogonal. These oligomers and several model compounds were singly reduced, and intramolecular electron hopping between the PDI molecules was probed by electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR) spectroscopy. When the functional groups attached to the ends of the oligomers were chosen to make each PDI molecule electronically equivalent, the single electron hops between the PDI molecules with rates that significantly exceed 10(7) s(-1). Rapid electron hopping between pairs of PDI molecules having orthogonal pi systems is unexpected and may expand the possible design motifs for organic electronic materials based on PDI.