The naming scheme for codoping in both the first and second coordination spheres is ring size (e.g., 6-membered), metal and oxidation state (e.g., Fe(II)), positions for dopant in the second coordination sphere (e.g., 6 and 13 to make 6-13, see Figure ), and the identity and number of the dopants in first (e.g., N4) and second coordination sphere (e.g., S2) for a configuration such as 6membered Ru(III)(6-13 N4-S2). We initially imposed an additional restriction that for atoms to be considered in the second sphere they had to be nearest neighbors to the first-coordination sphere dopants. We then expanded this definition, as motivated by experimental studies , to also include three types of bridging configurations (i.e., 5-membered Fe(II)(2-5 N4-X2), 5-membered Fe(II)(2-8 N4-X2), and 6-membered Fe(II)(4-9 N4-X2), where X is any co-dopant, see Supporting