3-diiminoisoindolines and their related compoundsfrom aromatic or heteroaromatic imidates and carbodiimides are reported via C–H bond activation. This reaction is the first example of a transition-metal-catalyzed insertion of carbodiimides into an aromatic or heteroaromatic C–H bond and a novel method for synthesizing 1,3-diiminoisoindolines and their related compounds. Unsymmetrical 1,3-diiminoisoindolines