The final stage of this study focused on halogenating complex drug-like intermediates, pharmaceuticals, and agrochemicals (Figure ). These structures often contain multiple (hetero)arenes, sites of reactivity, and Lewis basic atoms, thus representing a significant synthetic challenge for the ring-opening, halogenation, ring-closing process. However, success in this endeavor would enable subsequent convergent coupling reactions, compound diversification, and late-stage functionalization efforts that are not possible with existing pyridine halogenation methods . We began our study by halogenating five polycyclic structures representative of drug-like intermediates and obtained reasonable yields of halogenated products as single regioisomers in these cases (58-64). A substituted quinoline containing a cyclic sultam was again brominated at C6 (65). Halopyridines 66-69 are notable as C-Hal bond formation occurs on one pyridine over another; we believe this selectivity results from exclusive NTf-pyridinium salt formation involving the less hindered heterocycle in each case . Pyridines 70 and 71 formed atropisomers during the one-pot halogenation process, raising the possibility of controlling axial chirality in further studies.