We used chlorobenzene 1a as a prototypical halogenated building block to assess the development of this strategy. 1a is used routinely in transition metal-catalyzed reactions with ipso-substitution of the chloride leaving group or in aryne chemistry to functionalize the ipso-and cine-positions 4 relative to the chloride leaving group (1 and 2-positions in Table ). We considered several different "onium" groups (Y + ) to install and then eject via ortho-deprotonation. We found thianthrenium to be an ideal "onium" activating group because it is installed with high selectivity at the 4-position relative to the chloride and is isolable by filtration in high purity and high (92%) yield. Additionally, the aryne is formed exclusively at the 3-and 4-positions relative to the chloride, which is retained (Table ). Using thianthrenium for this strategy, our standard conditions produce the aryne adduct 2a in 75% NMR-yield over two-steps (Table , entry 1). The related dibenzothiophenium (DBT + ) group was an inferior "onium" group for this purpose as we observed a 51% two-step yield of 2a (Table , entry 2). Although iodomesitylene has recently received considerable attention as a leaving group for deprotonative methods to access arynes, 11 all attempts to generate the required diaryliodonium salt 1a(MesI + ) were unsuccessful, even under forcing conditions (Table , entry 3). 12 We surveyed several other, more electron-rich arenes, but also observed low yield of diaryliodonium salts. Finally, non-"onium" leaving groups, are unreactive under our standard conditions to generate arynes (Table , entry 4). This observation corroborates the critical role of "onium" leaving groups for mild generation of arynes and suggests the functional group compatibility of halides as handles for further functionalization.