Site-specific coordination of synthetic metal complexes to proteins plays a crucial role in the development of stereoselective artificial metalloenzymes (ArMs), wherein the protein scaffold forms a secondary coordination sphere around the reactive centre providing stereocontrol . To synthesise ArMs, researchers have used many different approaches from simply leveraging native metal-binding activity found in certain proteins to combining synthetic chemistry and proteins, including using variants of natural cofactors, such as the iron-binding protoporphyrin IX, with alternative transition metals . More synthetic approaches to sitespecific incorporation of metal complexes include the utilisation of supramolecular binding, with several different tethered transition metal complex systems explored to date, the most notable being the biotin-streptavidin (Sav) system . Bioconjugation of metal complexes via covalent attachment with unique reactive amino acid residues such as cysteine or azidophenylalanine is another widely used approach to prepare ArMs . In vivo ligand incorporation offers an attractive alternative where metal-binding unnatural amino acids such as (2,2'-bipyridin-5-yl)alanine (BpyAla) can be selectively introduced to the protein scaffold directly using genetic code expansion technologies, allowing for more streamlined enzyme engineering .