Methods of functionalizing α-halogenated hydroxy acid-based polymers and coupling α-halogenated hydroxy acid-based polymers are provided. Suitable α-halogenated hydroxy acid-based polymers include α-halogenated polyesters and α-halogenated acrylate-based inimers. Methods include coupling α-halogenated polyesters and functionalizing α-halogenated polyesters without polymer cleavage. Certain α-halogenated hydroxy acid-based polymers may be functionalized, crosslinked or, intiate polymerization by inducing the α-halogenated hydroxy acid-based polymers to make a dioxolenium ion intermediate. The α-halogenated hydroxy acid-based polymers may also be functionalized using a radical trap.