1,2,3,4-Cyclobutanetetracarboxylic dianhydride (CBDA, CAS 4415-87-6) is a high-purity, rigid cycloaliphatic (alicyclic) dianhydride monomer supplied by AureChem that is primarily used in the synthesis of high-performance polyimides and related polymers, where it provides a desirable combination of excellent transparency, low color, low dielectric constant, thermal stability, mechanical strength, a