The present invention relates to polymers comprising diazine, especially pyrimidine, containing repeating units. Optical devices, comprising the polymers of the present invention, can show significant advantages in color purity, device efficiency and/or operational lifetime. In addition, the polymers can have good solubility characteristics and relatively high glass transition temperatures, which facilitates their fabrication into coatings and films that are relatively thin, thermally stable, and relatively free of defects.