affording the heterocoupled product in the presence of anhydrous iron(III) chloride in a modest 60:40 e.r. Both yield and e.r. were improved (80% yield at 75:25 e.r.) on switching to the hexahydrate salt (which is both cheaper and easier to handle; Table , entry 5). We recognized that the group at C-3 of the naphthol partner might also have an impact beyond enhancing chemoselectivity and found that e.r. of 3d increased (to 84:16) with a larger (phenyl) ester group. We subsequently explored different PyBOX ligands in combination with changes at the C-3 ester, finding that the combination of 1-naphthyl substituted PyBOX ligand L4 with a 2-isopropylphenyl ester substrate afforded the heterobiaryl product 3e in 63% yield and 92:8 e.r. (Table , entry 12). Modulation of reaction time, an increase in the quantity of ligand (to 12 mol%) and indole (to 1.5 eq.) and sonication of the Fe salt prior to ligand addition all continued the aggregation of marginal gains to ultimately afford the desired heterocoupled biaryl product in 91% yield and 94:6 e.r. With an optimized set of reaction conditions, we explored the substrate scope for the reaction (Figure ). In all cases, the mass balance is accounted for as unreacted naphthol starting material, and the 3,3'bisindole product 5 is not observed.