Photochemistry has enabled numerous unique transformations using light as a green energy source. Carbonyl compounds have been known since a long time as one of the most important photoactive species in both synthetic and biological applications. They can be used as either photoactive substrates or as photocatalysts as exemplified by thioxanthone or benzophenone. The excitation of carbonyl compounds can be achieved via either energy transfer catalysis or direct excitation (Scheme 1A). Although energy transfer catalysis provides milder conditions to activate molecules with a low-energy light source, extensive optimization of the photocatalyst is usually required. Furthermore, electron transfer pathways are usually a competitive mechanism, leading to the formation of by-products. Alternatively, the direct excitation of carbonyl compounds enables several well-known transformations, such as the Paternò-Büchi 9 or Norrish-type reactions. 10 However, most studies focused on alkene-conjugated carbonyl compounds since the extended conjugated system makes them highly photoreactive. Excitation of the  system of either the C=O or the C=C bond can occur, leading to Paternò-Büchi reactions 9 or [2+n] annulations. These transformations have been studied intensively since the start of photochemistry and have seen renewed interest in the past few decades. In contrast, the homolytic fission of  C-C  bonds in carbonyl compounds is underdeveloped due to two main reasons: i. The excitation of -carbonyl compounds requires higher energy than -conjugated systems, ii. The bond dissociation energy of  bonds is much larger than the one of  bonds, making the process thermodynamically challenging.