For fluoro-quinolone carboxylic acid derivatives, one bond carbon-fluorine coupling constants are ranged from 249 ㎐ to 257 ㎐ regardless of positions. But geminal and vicinal carbon-fluorine coupling constants vary according to positions, namely, geminal coupling constants are ranged from 6 ㎐ to 23 ㎐, and vicinal coupling constants are ranged from 1.9 ㎐ to 7 ㎐. In cases of proton-fluorine couplings, three bond coupling constants are ranged from 9 ㎐ to 10.3 ㎐, and four bond coupling constants ate ranged from 6 ㎐ to 8.3 ㎐.