1,3-Dipole-functional compounds (e.g., azide functional compounds) can be reacted with certain alkynes in a cyclization reaction to form heterocyclic compounds. Useful alkynes (e.g., strained, cyclic alkynes) and methods of making such alkynes are also disclosed. The reaction of 1,3-dipole-functional compounds with alkynes can be used for a wide variety of applications including the immobilization of biomolecules on a substrate.