A series of 4-methoxycarbonylisoquinoline-1,3-diones was obtained from homophthalic acid in four steps. The key step was the quantitative and rapid alkalinecyclization of 2-methoxycarbonyl-2-(2-methoxycarbonylphenyl) acetamides. Homologation easily afforded in the same conditions 5-carboxy-2-benzazepine-1,3-dione. J. Heterocyclic Chem., 46, 392 (2009).