Barltrop and Schofield first demonstrated the use of a benzyl-based PPG, structural variations have focused on substitution to the benzene ring, as well as extension of the aromatic core. For example, insertion of a m,m’-dimethoxy substituent was shown to increase the chemical yield ~75% due to what has been termed the “excited state meta effect.” However, this substitution is only able to release good leaving groups such as carbamates and carboxylates. Additionally, the addition of an o-hydroxy group enables the release of alcohols, phenols and carboxylic acids due to the proximity of the phenolic hydroxy to the benzylic leaving group. Finally, the carbon skeleton has been expanded to include PPGs based on naphthalene, anthracene, phenanthrene, pyrene and perylene cores, resulting in varied chemical and quantum yields, as well as irradiation wavelengths and times.