Radical chemistry has greatly affected polymer science, allowing an increasingly large diversity of polymers to be made robustly and reliably. More recently, with the development of reversible deactivation radical polymerisation (RDRP), polymers can be synthesised with controlled and near uniform molecular weights, allowing precision at the atomic scale. The continual introduction of novel photocatalytic radical chemistry into existing RDRP processes has led to a rapidly propagating area of polymer research in recent years. The Polymer Nanostructures Group at the University of Sydney, led by Markus Müllner, has recently introduced bismuth oxide (a visible band gap semiconductor) as a heterogeneous photocatalyst for polymerisation by photo-induced electron transfer (PET) that operates at room temperature and with visible light (Hakobyan K., Gegenhuber T., McErlean C.S.P., Müllner M. Angew. Chem. Int. Ed. 2019, 58, 1828–32). Bismuth oxide introduces favourable properties to PET-RDRP, such as low toxicity, reusability, low cost, and ease of removal from the reaction mixture. Formidable control normally associated with degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition–fragmentation chain-transfer (RAFT) polymerisation, was observed. Homopolymers and diblock copolymers with differently activated monomers were successfully synthesised, while the PET process allowed excellent temporal control of the polymerisations.