The potential negative impact on catalyst activity of the recycling process was taken into consideration and tested by performing alkylation reactions with TBADT that was obtained either via OSN or via non-solvent extraction and filtration. In both cases, product yields comparable to those achieved with pristine TBADT were measured (Figure and Table in Supplementary Information). This result highlights that catalyst recycling has no observable detrimental effects on the stability and catalytic activity of TBADT. We believe this is due to the molecular structure of TBADT which is not prone for radical attack. This is in contrast to organic dyes and Ru-or Ir-based photocatalysts where the ligands, often polypyridyl moieties, are excellent acceptors for radicals and are the main cause for catalyst degradation. When moving from TBADT solution to the reaction mixture, undesired interactions of substances in the reaction mixture, such as starting materials, products or byproducts, with the membrane may negatively affect filtration performance. Therefore, to evaluate potentially undesired effects of chemicals present in the reaction mixture, filtration experiments were performed with mixtures containing an increasing number of substances: TBADT, TBADT and cyclohexane, and the complete reaction mixture. For all experiments, comparable fluxes were observed (Figure in Supplementary Information). Therefore, a negative influence of reaction components, particularly cyclohexane, was ruled out.