In order to introduce the C-O-N linkage at the polymer chain end, the reactions of poly(styryllithium) with 1-oxo-4-methoxy-2,2,6,6-tetramethylpiperidinium salt (OAS) and with the corresponding nitroxyl radical (MTEMPO) were investigated in THF at -78-degrees-C. The aminoxy terminal was found to be introduced in quantitative efficiency by the reactions of the living polymer with OAS in the presence of MTEMPO. It is considered that the reactions proceed via one-electron transfer from the polystyryl anion to OAS, resulting in the polymer radical, which is coupled with MTEMPO to yield the polystyrens with an aminoxy terminal. Similarly, the electron-transfer reaction proceeded between the poly(styryllithium) and MTEMPO to yield the aminoxy-terminated polystyrene quantitatively. The resulting polystyrene could initiate the radical polymerizations of methyl, ethyl, and butyl acrylates to afford the corresponding block copolymers.