Perrin's equation for solute quenching is redefined. Multicomponent concentration quenching curves are obtained by plotting log (I/c) vs. c. Addition of quencher to the solvent-solute system and use of inefficient solvent cause the quenching curves to become linear. Based on the shift of maximum activating wavelength during photo-activation, formation of excimers or molecular aggregates of similar nature is postulated to explain the observed phenomenon.