The article reviews the recent progress in sulfur-containing high refractive index (HRI) polymers for optical applications. Sulfur, due to its high molar refraction, plays a crucial role in enhancing the refractive index of polymers, making them suitable for various optical devices such as image sensors, optical data storage, antireflective coatings, light-emitting diodes, and nanoimprinting. The review covers the chemistry of bonding and the optical properties of polymers containing sulfur and selenium, focusing on their synthesis, properties, and applications. Key aspects discussed include the interplay between refractive index and other polymer properties, the design of high refractive index materials, and the challenges in achieving high transparency in the visible range. The article also highlights the importance of sulfur-containing polymers in nanoimprinted optical circuits, OLEDs, image sensors, and antireflective coatings. Additionally, it explores the synthetic procedures for sulfur-containing polymers, including inverse vulcanization and thiol-ene click chemistry, and provides a comparative analysis of different sulfur-containing polymers in terms of their refractive indices and transparency.The article reviews the recent progress in sulfur-containing high refractive index (HRI) polymers for optical applications. Sulfur, due to its high molar refraction, plays a crucial role in enhancing the refractive index of polymers, making them suitable for various optical devices such as image sensors, optical data storage, antireflective coatings, light-emitting diodes, and nanoimprinting. The review covers the chemistry of bonding and the optical properties of polymers containing sulfur and selenium, focusing on their synthesis, properties, and applications. Key aspects discussed include the interplay between refractive index and other polymer properties, the design of high refractive index materials, and the challenges in achieving high transparency in the visible range. The article also highlights the importance of sulfur-containing polymers in nanoimprinted optical circuits, OLEDs, image sensors, and antireflective coatings. Additionally, it explores the synthetic procedures for sulfur-containing polymers, including inverse vulcanization and thiol-ene click chemistry, and provides a comparative analysis of different sulfur-containing polymers in terms of their refractive indices and transparency.