A series of quinoline and naphthyridine antibacterial agents possessing an acyclic or cyclic gem-disubstituted piperazine substituent at the C-7 position have been prepared and evaluated in vitro and in vivo for antibacterial activity against a variety of Gram-positive and Gram-negative organisms. They are, however, not as active as quinolones or naphthyridines with a monosubstituted piperazine substituent at C-7. The chemical synthesis of these derivatives is also described.