A palladium-catalyzed intramolecular C(sp²)–H amination of phenylalanine moieties in dipeptides is described. By this protocol, a series of indoline-2-carboxylate-containing dipeptides were synthesized from dipeptides. The N-protected amino acid moiety within the peptide is used as an intrinsic bidentate directing group. This intramolecular C–H amination reaction provides an appealing strategy for the post-synthetic modification of peptides.