This review summarizes the catalyst- and solvent-free grafting and cross-linking of common polymers with unsaturated bonds exploiting kinetically stabilized nitrile N-oxides via click process. The nitrile N-oxides enable the efficient 1,3-dipolar cycloaddition to internal olefins, nitrile groups, and alkynes incorporated into versatile polymers such as polyacrylonitrile(PAN), natural rubber(NR), acrylonitrile butadiene rubber(NBR), ethylene-propylene-diene terpolymer(EPDM), and internal alkyne-containing polymer to give the corresponding functionalized polymers. The reaction features i)catalyst-free procedure, ii)versatile applicability to various polymers, iii)high yield, iv)no byproduct, and v)remarkable acceleration of reaction rate under solvent-free condition. The applications of the stable nitrile N-oxidebased reactions to cross-linking reaction are also discussed.