Stationary photoconduction in either a phenyl-substituted poly-phenylenevinylene copolymer (PhPPV) or an alkylated hexa-peri-hexabenzocoronene (HBC) doped by perylenediimide (PdI) at a broad range of dopant concentrations has been measured and compared to previous results on PhPPV doped by trinitrofluorenone (TNF). At moderate concentration, the yield of the photogeneration is virtually invariant regardless of the system and blend ratio because practically every primary excitation dissociates at a donor-acceptor site and the subsequent escape from the coulombic potential is virtually system-independent. At dopant concentrations >10% the yield of that escape process increases by two to three orders of magnitude. (C) 2003 American Institute of Physics.