[*] D. Birnthaler, R. Narobe, To unlock access to the synthetic potential different elements may offer, we sought to design a systematic, rational screening assay for accelerated identification of LMCT activity across the periodic table . To begin, we focused on identifying a suitable test system allowing a conclusive qualitative readout. The reaction of choice should produce an easily detectable product without any major side reactions. The only essential requirement for product formation should be a LMCT step of the metal catalyst. Leveraging net oxidative reactions with oxygen as terminal oxidant and using a 96-well plate setup becomes a simple choice for fast high-throughput screening (see Figure ). Out of reported aerobic decarboxylative oxidation, benzylic C(sp 3 )-H oxidation, oxidative cleavage of diols, and dehydrogenative lactonization of 2-arylbenzoic acids, the lastly mentioned transformation caught our attention. Cerium and iron based systems are described in literature to give the respective coumarin 1b under diverse reaction conditions. In this reaction, the key intermediate -a highly reactive carboxylate radicalundergoes rapid intramolecular addition to the tethered phenyl ring which then gets quickly oxidized and rearomatized.