Synthesis of [1]benzothienonaphthyridines

3-Chlorobenzo[b]thiophene-2-carbonyl chloride reacted readily with 2-amino-, 3-amino-, or 4-aminopyridine to give the corresponding amides. Photocyclization of the amides afforded the following lactams: [1]ben-zothieno[2,3-c][1,5]naphthyridin-6(5H)-one (14), [1]benzothieno[2,3-c][1,6]naphthyridin-6(5H)-one (7), [1]benzo-thieno[2,3-c][1,7]naphthyridin-6(5H)-one (11), and [1]benzothieno[2,3-c][1,8]naphthyridin-6(5H)-one (3). These lactams have been converted to other derivatives including in two instances the unsubstituted ring system.