Herein, we provide the proof-of-concept studies. When R is a H-atom, the polymerization proceeds via 1,5-HAT, leading to the AAB sequence-defined polymers, analogous to the ordered copolymers of ethylene and 1,1-disubstituted ethylene. When R is a cyano group, the polymerization proceeds via 1,5-cyano transfer, leading to the ABC sequence-defined polymers, analogous to the terpolymer comprising of ethylene, acrylonitrile, and 1,1-disubstituted ethylene. Of note, all these sequence-defined polyethylene-based polymers are difficult to prepare by current methods.