The donor-acceptor-type norbornadiene (D-A NBD) 1,4,5,6-tetramethyl-3-phenyl-2,5-NBD-2-carboxylic acid was prepared by the Diels-Alder reaction of methyl 3-phenylprop-2-ynoate with 1,2,3,4-tetramethyl-1,3-cyclopentadiene. 1,4,5,6,7-Pentamethyl-3-phenyl-2,5-NBD-2-carboxylic acid was also synthesized in the same way. Styrene-type polymers with pendant D-A NBD moieties were prepared with a 100% degree of substitution (DS) by the reaction of D-A NBD carboxylic acids with poly[(p-chloromethyl)styrene] with 1,8-diazabicyclo[5.4.0]undecene-7 in dimethyl sulfoxide at 70 degreesC for 6 h. In the reaction of D-A NBD carboxylic acids with poly(2-chloroethyl vinyl ether), the DSs were about 60%. The photochemical valence isomerizations of all the NBD polymers proceeded smoothly with UV irradiation in tetrahydrofuran solutions and in the film state. In addition, the rate of the photochemical reaction of the NBD polymers increased efficiently by the addition of 4,4 ' -bis(diethylamino)benzophenone as a photosensitizer in a film state. The stored thermal energy of the irradiated polymers was also evaluated by differential scanning calorimetry to be 55-74 kJ/mol.