Dehydrohalogenation of haloaromatics in ionic liquids derived from ethylmethylimidazolium or similar salts has been performed using Pd-C, Pd(OAc)₂ and other catalysts using formate salts as a hydrogen source. In the ionic liquid [emim][BF₄], chlorobenzene was dehalogenated by up to 40%, bromobenzene up to 25% and iodobenzene up to 41% in 2 h. Reactions in the absence of the ionic liquid were also performed.