High refractive index polymers (HRIPs) have drawn attention for their optoelectronic applications and HRIPs with excellent transparency and facile preparation are highly demanded. Herein, sulfur-containing all organic HRIPs with refractive indices up to 1.8433 at 589 nm and excellent optical transparency even in one hundred micrometre scale in the visual and RI region as well as high weight-average molecular weights (up to 44500) are prepared by our developed organobase catalyzed polymerization of bromoalkynes and dithiophenols in yields up to 92%. Notably, the fabricated optical transmission waveguides using the resultant HRIP with the highest refractive index display a reduced propagation loss compared with that generated by the commercial material of SU-8. In addition, the tetraphenylethylene containing polymer not only exhibits a reduced propagation loss, but also is used to examine the uniformity and continuity of optical waveguides with naked eyes because of its aggregation-induced emission feature.