The initial conditions for the experiments were established in batch for the palladium-catalyzed Suzuki coupling between 4-iodoanisole, carbon monoxide and 4-fluorophenylboronic acid. Various headspace compositions were analyzed to optimize the reaction and evaluate its compatibility with other gases (e.g., H2) present in the mixture (see Supplementary Information). A decrease in reactivity was noted, possibly attributed to the formation of an inactive palladium precipitate due to hydrogen presence. To address this, a combination of Pd(OAc)2 and XantPhos was employed. For the carbonylative Suzuki coupling, a fed-batch approach was adopted, with the boronic acid added dropwise to the reactor flask while continuously purging the gaseous outlet of the photoreactor through the reaction mixture.