High refractive index polymers(HRIPs)have been widely utilized in optical and optoelectronic devices due to their advantages of light weight

flexibility

high impact strength and easy processing. The refractive indices of polymers mainly depend on their chemical structures. Introducing highly polarizable atoms or groups such as aromatic rings

sulfur-containing groups

halogens(except fluorine)

organometallic moieties

and fullerenes into the polymers can efficiently enhance their refractive indices. Therefore

the refractive index value of a polymer can be tuned in the way of molecular tailoring

which provides good insight in developing new high refractive index polymers. This mini-review summarizes principles in molecular designing and recent progresses in high refractive index polymers.