Photochemical process in which a reaction of a non-absorbing substrate is induced by electron transfer (not energy transfer) with an excited light-absorbing sensitizer. The overall process must be such that the sensitizer is recycled. Depending on the action of the excited sensitizer as electron donor or acceptor the sensitization is called reductive or oxidative.
See also: photosensitization
PAC, 1996, 68, 2223. 'Glossary of terms used in photochemistry (IUPAC Recommendations 1996)' on page 2239 (https://doi.org/10.1351/pac199668122223)