Indicator displacement assays based on the organometallic complex [Cp*RhCl2]2 and the dye gallocyanine have been used to sense aminosugars and aminoglycosides in buffered aqueous solution by UV-Vis spectroscopy. The data of three assays at pH 7.0, 8.0 and 9.0 were sufficient to distinguish the aminosugars galactosamine, glucosamine, mannosamine and the aminoglycosides kanamycin A, kanamycin B, amikacin, apramycin, paromomycin and streptomycin. Furthermore, the assays were used to characterize mixtures of aminoglycosides and obtain quantitative information about the respective analytes.