This work was carried out in order to demonstrate that polymers with tunable, high refractive index values can be designed and synthesized to fit a variety of optical applications. A series of polyphosphazenes bearing conjugated, organic side groups were synthesized and their refractive indices were measured. Refractive index values ranging from 1.60 to 1.75 were obtained. A systematic approach to tailoring various polymer properties such as refractive index, optical absorption, solubility, and glass transition temperature was utilized in the synthesis of these polymers. Control over the extent of conjugation of the side group, side group molecular symmetry, and the use of a molecular spacer group were employed to achieve this goal. These polymers can be cast from solution and used in applications that require optically transparent films.