Steady-state and time-resolved fluorescence behavior of 1,3-bis(1-pyrenyl)propane have been investigated in four different room temperature ionic liquids. It is found that the excimer to monomer fluorescence intensity ratio of the system in the room temperature ionic liquids is significantly lower than that observed in conventional solvents. A detailed analysis of the fluorescence decay profiles of the monomer and excimer reveals that even though the mechanism of intramolecular excimer formation in room temperature ionic liquids is similar to that in conventional solvents, the kinetics of the formation of the excimer is considerably slower in the former media. (C) 2003 Elsevier B.V. All rights reserved.