Copolymers of epsilon-caprolactone (CL) and trimethylene carbonate (TMC) have been synthesized through ring-opening polymerization using a novel initiator of scandium tris(2,6-di-tert-butyl-4-methylphenolate). CL and TMC polymerizations proceed via the "coordination anionic mechanism" with acyl-oxygen bond cleavage. Five kinds of copolymers with different structures of X, XB, AXB, AB, and BAY-B are synthesized under different polymerization conditions and characterized by H-1 NMR, GPC, and DSC, where X, A, and B denote as random blocks of CL and TMC, PTMC blocks, and PCL blocks, respectively.