O-Dihaloarenes as aryne precursors for nickel-catalyzed [2+2+2]cycloaddition with alkynes and nitriles

o-Dihaloarenes acting as aryne precursors react with acetylenes and nitriles catalyzed by the NiBr2(dppe)/dppe/Zn system to give substituted naphthalene, phenanthridine or triphenylene derivatives depending on the reaction conditions in moderate to excellent yields with good tolerance of functional groups.