Norfloxacin complexes of $Fe^{2+}$, $Cu^{2+}$ and $Al^{3+}$ have been prepared as solids. The stoichiometry of the complexes has been established. IR investigation indicates the metal-ligating sites in norfloxacin. The bioactivities of complexes all lower than that of norfloxacin. The solubilities and partition coefficients have been measured as a function of temperature. The data are used to evaluate the thermodynamic parameters ${Delta}G$, ${Delta}H$, ${Delta}S$ for the solute transfer process and compared with the parent quinolone, norfloxacin. The existence of such complexes is discussed in the light of quinolone mode-of-action theories.