The reduction of fluorescence intensities and of fluorescence lifetimes is determined as a function of carbon disulfide (CS2) concentration for four fluorophores. The quenching efficiency of CS2 depends strongly on the energy of the electronic absorption edge of the dye; quenching increases as the dye electronic edge approaches that of CS2. These results are described by the quantum two-level system. Comparison of Stern-Volmer plots of intensity and lifetime data shows that quenching is predominantly diffusion-mediated and furthermore demonstrates that the interaction range is about 6 (A) over cap. The impact of CS2 on the fluorescence spectra of important natural materials is discussed.