APP is a diamine compound containing pyridazine and sulfur.

Since molecular and atomic refractive indices of the pyridazine and sulfur atom are high, it can be used as a raw material for high refractive index polyimide.

By polymerizing with various tetracarboxylic dianhydride, it is expected to be used as a polyimide resin with transparency, high refractive index, low birefringence, and heat resistance.