Functional (co)polymers are increasingly developed by ring-opening polymerization of functional cyclic esters and cyclic carbonates for a wide range of applications. Following this trend and aiming to challenge the polymerization of γ-thiolactones, we studied the ring-opening copolymerization of functional γ-thiolactones with trimethylene carbonate in order to prepare new poly(carbonate-co-thioester)s with phosphonated or fluorinated pendant groups.