Despite great advances over the past decade, the field of bioconjugation remains deficient in some key areas. For example, reactions with high rate constants in biological media are important but rare. Since the rate of chemical coupling reactions decrease quadratically with concentration, high-rate constant reactions are essential to monitor biological processes at relevant concentrations. My group has developed a series of high-rate constant coupling reactions and in the present proposal we outline how these reactions could be exploited in chemical biology.