"Click chemistry" is defined as a class of robust and selective chemical reactions affording high yields and is tolerant to a variety of solvents (including water), functional groups and air.The previously known copper-catalyzed Huisgen cycloaddition of alkynes and azides is considered to be particularly useful for rapid and facile modification of surfaces.The reaction proceeds in aqueous solvents and in the presence of air to yield stable 1,2,3-triazoles.The most commonly used click mode is to immobilize functional molecules with a terminal alkyne group to azide-modified supports which includes immobilization of cinchona alkaloid derivatives onto azide-modified silica surfaces,polymers onto glass and silica surfaces, and self-assembled monolayers onto electrode surfaces.