Magnetic field effect (MFE) on pyrene-DMA exciplex luminescence and exciplex lifetime have been studied in reverse micelle of Aerosol-OT in n-heptane in presence of N,N-dimethylformamide and methanol as the polar solvent at different W-s (W-s = [polar solvent]/[surfactant]) values. It is found that two types of exciplexes are residing at different locations of the non-aqueous reverse micelle. Out of these only the exciplex emitting at longer wavelength is found to be field sensitive. The higher MFE and shorter lifetime of the exciplex in non-aqueous reverse micelle compared to that of aqueous micelle have been explained on the basis of presence of hydrogen bonding and dipolar interaction between the solvent and the polar head group of the micelle. (c) 2006 Elsevier B.V. All rights reserved.