The variation of the photocurrent with temperature is found to obey the relation i = i0e−E/RT in naphthalene, stilbene, diphenyl, terphenyl, β-methylanthracene, anthracene, azulene, and pyrene. The activation energies have been measured and are found to increase in the above order. These activation energies show no apparent correlation with the corresponding activation energy of semiconduction, and it is suggested they are associated with the charge carrier transport process.