Cyclopolymerization of benzaldehyde divinyl acetal (1) and 1,2-divinyloxybenzene (4) was carried out using (+)- or (-)-camphorsulfonic acid [(+)- or (-)2]/ZnCl2 initiating system. Polymer 3 obtained from monomer 1 consisted essentially of cyclic repeating units, whereas polymer 5 from 4 possessed a small amount of residual vinyloxy groups. Both polymers 3 and 5 using (+)-2/ZnCl2 showed optical activity with a negative sign of optical rotation. The molar optical rotation values of polymer 3 using ZnCl2 . OEt(2) were larger than those using ZnCl2. The CD spectra of the polymer with [Phi](20)(435) = -30.1 degrees ((-)-3) and (4S,6S)-4,6-dimethyl-2-phenyl-1,3-dioxane showed a negative Cotton effect at 210 nm, whereas the polymer with [Phi](20)(435) = +24.1 degrees ((+)-3)and (4R,6R)-4,6-dimethyl-2-phenyl-1,3-dioxane had mirror image CD curves with a positive Cotton effect at 210 nm. The absolute configurations of the major chiral cyclic units in (-)- and (+)-3 were the SS- and RR-forms, respectively.