Efficient and selective direct synthesis of diarylamines from aryl halides and arginine as a nitrogen‐donor reagent is reported. Arginine, which is an oral supplement, acts as a useful nitrogen source donor in the copper‐catalyzed reaction. Fe3O4/Cu3(BTC)2, which was easily separated and recycled with a magnet, improved the rate and facilitation of the synthesis of diarylamines selectively. The introduction of a new and available N‐source, simple magnetic separation process, normal atmospheric conditions, and excellent yields under mild reaction conditions are other important features of this work.