As a substituted-δ-valerolactone, α-ethylidene-δ-vinyl-δ-valerolactone (EVL) provides a method of utilizing carbon dioxide with 1,3-butadiene to produce functional polymers. Its di-ene-substituted lactone ring was considered inactive in polymerization in the past two decades, while successful polymerization attempts of EVL have been reported very recently. Novel synthetic strategies and functional polymers from EVL have been developed. The ring-opening reactions of EVL and the corresponding polymers as well as the ring-opening (co)polymerizations of EVL and its derivatives are highlighted in this review. The obtained functional polymers with or without facile post-polymerization modification possess unique properties, such as amphipathy, elasticity, peel resistance, etc., allowing for application potential in various fields.