Bioorthogonal chemistry offers a powerful tool to study protein structure, dynamics, and function in living systems. Recently, we have developed a photoinducible, nitrle imine mediated 1,3-diplor cycloaddition as a bioorthogonal reaction, and demonstrated its utility in selective protein labeling both in vitro and in vivo. In this talk, the scope of this reaction as well as the applications of this chemistry in various biological systems will be discussed.