Two series of poly(benzoxazine‐ether‐urethane)s (PBEUs) are prepared through thermally activated ring‐opening polymerization (ROP) of bi‐functional benzoxazines containing ether‐urethane moieties. The bi‐functional benzoxazines are synthesized through coupling reaction of hydroxyl‐containing mono‐functional monomers based on phenol, o‐allylphenol, o‐cresol, p‐cresol, diglycolamine, and paraformaldehyde with 1,6‐hexamethylene diisocyanate (HDI) and 2,4‐toluene diisocyanate (TDI), respectively. The ROP temperature of each HDI‐based benzoxazine is higher than that of the counterpart based on TDI, and they are in descending order ortho‐, para‐, and unsubstituted phenol for both series. Due to the difference in structure symmetry between the two series monomers, the variation of polymerization rate with temperature of each TDI‐based benzoxazine is different from that of the counterpart based on HDI. The ortho‐ and para‐substituted‐phenol‐based PBEUs show lower glass transition temperatures than that of the phenol‐based counterpart. In the vicinity of the glass transition temperature, the HDI‐based PBEUs exhibit thermally induced one‐way dual‐shape memory effect.