1-(3-Methylphenyl)-1H-pyrrole-2,5-dione (CAS 20299-79-0) has a molecular formula of C??H?NO? and a molecular weight of 187.19 g/mol, with a 3-methylphenyl group attached to the N-atom of the pyrrole-2,5-dione core. As a functional cyclic imide intermediate, it is widely used in synthesizing polymers, pharmaceuticals, and fine chemicals. It should be stored sealed in a cool, dry place to avoid hydrolysis or thermal degradation, maintaining reactivity for synthetic applications.