AbstractInclusion polymerization of cyclic diene monomers, such as cyclopentadiene, 1,3‐cyclohexadiene, 1,3‐cycloheptadiene, 1,5‐cyclooctadiene, and 2,5‐norbornadiene, was studied, using deoxycholic acid (DCA) as the canal component.The formation of monomer‐DCA adducts was observed, however, the polymerization occurred only in the case of cyclopentadiene, 1,3‐cyclohexadiene, or 1,3‐cycloheptadiene. The polymers obtained consisted preferably of 1,4‐units and almost 100% of 1,4‐units in the case of 1,3‐cyclohexadiene. ESR measurements revealed that inclusion polymerization of cyclopentadiene or 1,3‐cyclohexadiene in DCA canals proceeds by a f