The mild decarboxylative oxidation of Mandelic acid and its derivatives is a common strategy to obtain aldehydes and ketones selectively. The parent α-hydroxy acids are readily available, bench-stable, and can be converted under both stoichiometric and catalytic conditions (vide infra). Mechanistically, the decarboxylative oxidation of α-hydroxy acids requires two key steps: the decarboxylation and the oxidation of the alcohol to the carbonyl functionality (Figure ). However, the sequence of events may vary with substrate and reaction conditions applied. Ultimately, both pathways will lead to carbonyl products. Previous methodologies for decarboxylative oxidation of Mandelic acids applied stoichiometric oxidants such as sodium hypochloride or sodium metaperiodate but generated additional waste. Moreover, mechanistic insights were gained from electrochemical studies. Catalytic approaches using Copper Aluminum hydrotalcite and Bismuth(0) catalysts yield Vanillin as the main product but inevitably produce Vanillic acid as a side product from overoxidation (Figure ). Similarly, while Cobalt-catalyzed conditions effectively yielded aldehydes for substrates bearing electron-donating groups (EDG), they resulted in overoxidation to benzoic acids when electron-withdrawing groups (EWG) were present, highlighting the need for selectivity in such transformations. In a nonheme model, Iron-catalysts have been applied for decarboxylative oxidation. Likewise, a hybrid Flavin and Nickel catalytic system yielded keto-acids instead of aldehydes, 9 while acetophenone and benzophenone were obtained in only two instances. These shortcomings emphasize the need for a more selective and efficient catalytic approach. Lately, photocatalysis has emerged as a powerful tool for the redox manipulation of organic molecules. For instance, Yu and co-workers demonstrated the synthesis of carbonyl products using 4CzIPN as photocatalyst. Nonetheless, this study was limited to only three examples and oxygen was required as the terminal oxidant, which resulting in the formation of reactive radical peroxide species. Similarly, Zaman and colleagues reported a comparable approach using Iridium and Copper catalysts with oxygen serving as the terminal oxidant again. Their reaction in dichloromethane at elevated temperature required an extended irradiation of 40 hours and exhibited only a limited substrate scope. Likewise, McClelland and Weiss illustrated the direct photocatalytic oxidation of benzyl alcohol using visiblelight-absorbing quantum dots (QDs) again with oxygen as terminal reagent, further underscoring the challenges of a narrow scope and potential overoxidation. To overcome the selectivity issues observed in the traditional decarboxylative oxidation, we hypothesized that kinetically separating the decarboxylation and alcohol oxidation would be advantageous. Inspired by the photocatalytic decarboxylation merged with Nickel catalysis, we propose that Mandelic acids should undergo the photo-induced decarboxylation to form the respective α-hydroxy radical. Such long-lived radical can be quickly trapped by a Nickel catalyst forming the key intermediate (Int, Figure ). This stable intermediate should then be susceptible to Nickel-catalyzed dehydrogenation conditions as developed by the Newhouse group. Additionally, the incorporation of aryl halides as additives is anticipated to facilitate the alcohol oxidation step, a strategy we recently found to enable the dehydrogenation of phenylalanine derivatives. Altogether we propose the Nickel-photocatalytic conversion of α-hydroxy acids that effectively decouples the decarboxylation and oxidation reaction steps, thereby enhancing the overall selectivity.