Novel thermoplastic poly(thioether sulfone)s, poly(TCDSH/DVS) and poly(BSMD/VSTCD), with high refractive indices and high Abbe's numbers have been developed using disulfanyltricyclo[5.2.1.0(2,6)]decane (TCDSH) and bis(vinylsulfone)tricyclo[5.2.1.0(2,6)]decane (VSTCD) based on tricyclo[5.2.1.0(2,6)]-decane moiety. TCDSH and VSTCD were easily prepared from dicydopentadiene via two or three steps and polymerized with divinyl sulfone (DVS) or 2,5-bis(sulfanylmethyl)-1,4-dithiane (BSMD) to give high molecular weight polymers (M-n = 19 300 and 28 400). The flexible, transparent, and amorphous films of poly(TCDSH/DVS) and poly(BSMD/VSTCD) were successfully prepared. They showed a good thermal stability with the 5% weight loss temperatures of around 300 degrees C in nitrogen, the glass transition temperatures of 74 and 113 C, high refractive indices of 1.6052 and 1.6228, and high Abbe numbers of 48.0 and 45.8, respectively. Poly(TCDSH/DVS) and poly(BMMD/VSTCD) with highly balanced thermal and optical properties are promising candidates for optical application, especially for lens materials.