Summary. In “one-pot” reactions, pyrrole-α-and β-aldehydes condense readily with 4-ethyl-3- methyl-3-pyrrolin-2-one to give isodipyrrinone analogs, which undergo intramolecular cyclization when the pyrrolealdehyde possesses an α or β-CO 2 R group. The resulting regioisomeric pyrroloindolizinediones, with structures confirmed by NMR analysis, exhibit strong fluorescence, with quantum yields (φ F) as high as 0.91 at λ em∼ 450–550 nm.