o-Chloro- and o-bromophenyl phenylsulfoxides and (3-bromo-4-pyridyl) phenylsulfoxide were treated with Grignard reagents to generate benzyne (or 3,4-pyridyne) in THF. The o-iodophenyl derivative, on the other hand, gave mainly o-(arylsulfinyl)phenyl Grignard reagent.