The efficient and versatile click chemistry based on 1,2,4-triazoline-3,5-dione (TAD) was used as one of the most potential postfunctionalizing pathways to specially design polymer nanostructure for dielectric materials. The block copolymer was synthesized by tandem ring-opening metathesis polymerization and metathesis cyclopolymerization and self-assembled into the core shell nanostructure in the selective solvent, which could be modified by TAD in a controlled manner by tuning the TAD feeding amount, enabling the Alder-ene reaction of TAD with the double bonds to occur first on the polynorbornene backbone in the shell and then the cascade Alder-ene and Diels-Alder reactions on the polyacetylene backbone bearing five-membered rings in the core. The modified block copolymers incorporating varied amount of urazole moieties exhibited enhanced dielectric constant from 16.2 to 20.3 and lowered dielectric loss from 0.031 to 0.013 to 0.009, which provides a new idea of the selective postfunctionalization of nanostructures in solution for regulating the polymer structure and properties.