We report experimental studies on the development of photoactivatable fluorophores for rapid, light-induced synthesis of protein conjugates. Proof-of-concept studies demonstrated that electronic excitation of photoactivatable BODIPY-ArN3 (1) in the presence of different proteins leads to efficient labeling in less than 10 min. After synthesis and isolation of the fluorescently tagged protein, photochemical conversion yields using human serum albumin and onartuzumab were 47 ± 7% and 42 ± 5%, respectively.