This Letter reports the photophysics of 4,4-diaminodiphenyl sulfone in anionic and cationic reverse micelles (RM). Decreased fluorescence intensity with significant blue shift of intramolecular charge transfer (ICT) fluorescence maximum and longer emission lifetime of the entrapped probe in motionally restricted water nano-pool of anionic RM could be observed. Bi-exponential decay in anionic RM appears due to polarity heterogeneity in the pool. In a nut shell, experiments establish that the probe is anchored in the micellar head group region of anionic RM vis-a-vis far away from the core in cationic RM. Increasing pool size show the opposite effect to the probe. (C) 2013 Elsevier B.V. All rights reserved.