This data corresponds to the study of the dynamics of charge transfer in an ultrathin p-n heterojunction of the organic molecule of pentacene and monolayer MoS2. The transient absorption spectroscopy measurements show that exciton dissociation occurs on an ultrafast timescale and that the charge separation is long-lived with respect to recombination and trapping mechanisms. DOI: 10.1021/acs.nanolett.6b03704