The photolysis of toluene/ozone, m-xylene/ozone, p-xylene/ozone, and mesitylene/ozone mixtures in argon matrices at 12 K with UV light of lambda greater than or equal to 280 nm leads to products with ketene functionalities. The identification of the molecular structures of these products is based on deuterium. isotopic shifts and agreement with density functional calculations. Other products from the toluene/O atom reaction include methylphenol and benzyl alcohol; phenols are also formed from the reaction of xylenes with O atoms and from the reaction of mesitylene with O atoms.