Due to its high specificity and reliability, "click chemistry" has become a valuable tool to prepare functional materials in several research disciplines. Apart from the modular and orthogonal approach, the number of "click" reactions that can exhibit reversibility of the covalent linkages is very few. The chemical structure of 1,2,4-triazoline-3,5-dione (TAD) is almost analogous to widely renowned maleimide, which has been enormously exploited as a dienophile in dynamic Diels-Alder (DA) click conjugation with furfuryl moieties at a relatively slower rate and elevated temperature. Herein, a new class of a reversible electrophilic substitution (ES) "click" pathway has been introduced for straightforward postpolymerization modification of furan polymethacrylate, synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization using TAD derivatives. The suitable (forward and backward) reaction pathway of TAD-derived "click" conjugation was elucidated via the density functional theory (DFT) study. The reversibility within the TAD-derived new sigma-covalent bonds at an elevated temperature was evidenced by the DFT study and differential scanning calorimetry (DSC) analysis and was further elucidated by "trans-ES-click" chemistry. A rheology experiment with a temperature sweep was performed to study the alteration of moduli, complex viscosity, and relative cross-link density of the TAD-derived polymer networks at different temperatures and at different TAD contents. The dynamism of furfuryl-TAD "ES-click" conjugation within cross-linked polymer enabled healing of its microscratch, which was monitored using an optical microscope and exemplified in the present perspective.