A route of synthesizing triblock terpolymers in a one‐pot, “one‐step” polymerization approach is presented. The combination of two distinct polymerization techniques through orthogonal catalyst/initiator functionalities attached to a polymeric linker furnishes novel pathways to ABC‐terpolymers. Both polymerizations have to be compatible regarding mechanisms, chosen monomers, and solvents. Here, an α,ω‐heterobifunctional poly(ethylene glycol) serves as polymeric catalyst/initiator to obtain triblock terpolymers of poly(norbornene)‐b‐poly(ethylene glycol)‐b‐poly(l ‐lactic acid) PNB‐PEG‐PLLA via simultaneous ring opening metathesis polymerization and ring opening polymerization in a fast one‐pot polymerization. Structural characterization of the polymers is provided via 1H‐, DOSY‐, and 1H,1H‐COSY‐NMR, while solution and thin film self‐assembly are investigated by dynamic light scattering and atomic force microscopy.
