In this chapter, we have discussed the history of the resurgence of thiol–ene/yne click chemistry in polymer science along with their mechanistic pathways under radical conditions either thermally or photochemically initiated. The recent instances of the utilization of the thiol–ene/yne click reaction for synthesis of polymeric networks, linear and hyperbranched polymers, and dendrimers are highlighted. Stereo-selective polymer synthesis via thiol–yne click polymerization is an important recent development that has also been discussed thoroughly. For the synthesis aspect, a catalyst-free greener approach is given priority along with the utilization of renewable resources, which is also a future direction for the synthesis of sustainable and environment-friendly polymer design. We anticipate that this contribution will provide a foundation to sketch the next-generation polymeric materials via thiol–ene/yne click chemistry for various applications, such as drug-delivery vehicles, biomaterials, high refractive index optical materials, photovoltaic materials, adhesives and coatings.