Herein, a regioselective,
late-stage two-step arene halogenation
method is reported. We propose how unusual Ni(I)/(III) catalysis is
enabled by a combination of aryl thianthrenium and Ni redox properties
that is hitherto unachieved with other (pseudo)halides. The catalyst
is accessed in situ from inexpensive NiCl2·6(H2O) and zinc without the need of supporting ligands.