The fluorescence quenching of 5-methyl-3-phenyl-2-[s-oxadiazol-2'-thioneñ5'-yl] indole by carbon tetrachloride (CCl4) and aniline in different solvents viz., dioxane, benzene, toluene, methanol, propanol has been carried out at room temperature to understand the role of quenching mechanisms. The Stern-Volmer plots have been found to be linear. As probability of quenching per encounter ‘p’ is less than unity, and the activation energy for quenching ‘Ea’ is greater than the activation energy of diffusion ‘Ed’, it is inferred that the fluorescence of quenching mechanism is not due to material diffusion alone.