para-Azoxyanisole (PAA) is a zwitterionic liquid crystal. In a solid state, it appears as a white powder, but when heated it forms a liquid crystal. As one of the first known and most readily prepared liquid crystals, p-azoxyanisole has been played an important role in the development of liquid crystal displays.
Its liquid crystal range is from 118 °C to 136 °C. The solid to nematic transition is at 118 °C and the nematic to isotropic liquid transition at 136 °C.