Both steady-state (SS) and time-resolved (TR) studies show that the fluorescence of the dye Nile red (NR) is quenched by various aromatic amines (ArA). Bimolecular quenching constants (k_q) from both SS and TR measurements are observed to match well, indicating that the interaction is dynamic in nature. The quenching interaction in the present systems has been attributed to electron transfer (ET) from ArA to excited NR, based on the variations in the k_q values with the oxidation potentials of the amines. The k_q values calculated within the framework of Marcus' outer-sphere ET theory at different free-energy changes (ΔG⁰) of the ET reactions match well with the experimental ones, supporting the ET mechanism in the systems studied. The reorganization energy (λ) estimated from the correlation of the experimental and the calculated k_q values is quite similar to the solvent reorganization energy (λ_s), calculated on the basis of the solvent dielectric continuum model along with the assumption that the reactants are the effective spheres. Although a modest error is involved in this λ_s calculation, the similarity in λ and λ_s values suggests that the solvent reorganization plays a dominant role in governing the ET dynamics in the present systems.