The copolymerization of olefins with gaseous SO2 presents an effective method for the direct preparation of aliphatic polysulfones (Fig. ). However, this copolymerization is constrained by the influence of ceiling temperature (Tc), above which depolymerization occurs, necessitating that reactions be conducted at low temperatures. The corrosive nature of SO2 also places higher demands on polymerization equipment. Additionally, the impact of stereoelectronic effects of different olefins sometimes leads to the uncontrollable sequence structure of polymers in the copolymerization, such as styrene/SO2 system. The lack of polar functionalities on aliphatic polysulfones may also cause the poor solubility in common solvents, which impedes chain propagation and ultimately generates a product with low molecular weight and wide distribution. These reasons undoubtedly deteriorate the applications of aliphatic polysulfones. Cyclic vinylsulfones (CVS) serve as a new monomer for constructing aliphatic polysulfones via a SO2-free strategy (Fig. ), in which sulfonyl radical engages in chain-propagation during free radical-mediated ring-opening polymerization. However, due to the difficult incorporation of extra polar pendants in CVS monomers, aliphatic polysulfones are also obtained with poor solubility. Moreover, random ring-opening of CVS during the polymerization leads to uncontrollable sequence of polymers, and the newly formed C=C bond in backbone results in poor thermal resistance. Therefore, the facile preparation of sequence-controlled aliphatic polysulfones with high molecular weights still remains a formidable challenge.