Addition polymerization of the carbon–nitrogen double bond in acetaldazine, the azomethine analog of 2,4-hexadiene, has been studied. No polymer was obtained by radical initiator, while an oligomer with molecular weight of 800–1200 was obtained by n-butyllithium in aprotic solvents. The structure of the oligomer thus obtained was investigated by IR, UV and mass spectroscopies and chemical functional tests. The oligomer was composed of 1,2-addition structure and 1,4-addition structure . It was confirmed that the comparison of the number of oligomers with the number of charged initiator indicated an easy occurrence of a proton transfer from the acetaldazine monomer to the propagating anion. In addition, the anionic polymerizability of acetaldazine is discussed using various initiators for anionic polymerization in comparison of the half-wave potential of acetaldazine with that of various vinyl compounds and butadiene.