Pyridazine-Type Sulfur-Containing Diamine 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 polymers such as polyimide.

It is expected to be used as thin-film coating materials such as antireflective coatings, and various optical components such as optical waveguides and microlenses.