Computational and experimental studies have been performed to investigate the photostability of a series of 6,13-bis(arylalkynyl)-substituted pentacenes in the presence of oxygen. These studies indicate that photostabilization occurs through a selective LUMO orbital stabilization as has been seen previously for 6,13-bis(triisopropylsilylethynyl)pentacene. Marcus theory analysis suggests that the difference in vibrational reorganization energies across all compounds is small and that the thermodynamic driving force for forward electron transfer is primarily responsible for the observed photostabilization.