A process of the present invention is directed toward conducting highly selective, high yield post-polymerization reactions on polypeptides to prepare functionalized polypeptides. In certain embodiments, the polypeptides can be prepared by ring opening polymerization of N-carboxyanhydrides. In certain embodiments, the post-polymerization reaction is a “click chemistry” reaction. In certain embodiment, the “click chemistry” reaction is a triazole-forming reaction involving an alkyne on the polypeptide and an azide.