The ring-opening alternating copolymerization of the wide availability of epoxides and anhydrides is a powerful route to prepare functionalized polyesters with extraordinary properties. However, to date, the copolymerization of less reactive trans-internal epoxide with cyclic anhydrides has remained relatively unexplored. Herein, we report the development of robust dinuclear chromium catalysts for the alternating copolymerization of trans-internal epoxides with cyclic anhydrides, affording the corresponding polyesters with a completely alternating structure. The use of chiral trans-internal epoxide exclusively led to the formation of stereoregular polyesters, two of which are typical semicrystalline materials with high melting temperatures.