Department of Chemistry, Kakatiya University, Warangal-506 009 Manuscript received 3 December 1985, accepted 5 September 1986 The condensation of 2-aminonicotinaldehyde (1) with substituted-2-hydrory-1- naphthyl styryl ketones (2) in the presence of glacial acetic acid containing a catalytic amount of concentrated sulphuric acid affords the corresponding 8-aryl-8H-naphtho��t[1'2' : 5,6]pyrano[4,3-b][1,8]naphthyridines (3). Structures of the products have been established on the basis of elemental analyses, and ir, pmr and mass spectral data. The compounds were also tested for their antibacterial activity.