In nature, benzylic C(sp3)-H bonds are easily oxidized to alcohol and aldehyde groups. These molecules have a wide range of application, for example as pharmaceutical compounds. The challenge in developing synthetic methods to gain access to benzylic alcohols and aldehydes is that, under most conditions, they are directly further oxidized to carboxylic acid groups. Stahl’s group developed a new approach (to be described in a forthcoming publication): The radical of phthalimido-N-oxyl (PINO) is used as hydrogen atom transfer reagent, abstracting a hydrogen atom from the benzylic position. Another PINO radical then traps the generated benzylic radical in a mechanism here referenced as PINOylation. This PINOylated compound can easily be further transformed into the desired alcohols and aldehydes via photochemical reaction. The PINOylated compounds and their specific mechanism of synthesis are of interest because they display significant scope. In one of two observed products, the PINO molecule is bonded to the substrate via a C-O bond. The other product, unexpectedly, has the O atom incorporated into the ring of PINO via expansion, and bonds to the substrate via a C-N bond. For almost all studied substrates, both products are observed, and their ratios are not influenced by varied reaction conditions. Of all variables, the different substituents on the substrates have the largest influence on the ratio and formation of products. This computational DFT study of the PINOylation reaction mechanism seeks to elucidate how substituents affect product ratios.