In this Letter, our aim is to determine the location of metal Nanoparticles (NPs) inside Room Temperature Ionic Liquid (RTIL)-containing microemulsions by solvation dynamics approach. To locate the NPs we have used three different coumarin probes, C-153, C-480, and C-343, due to their different locations in RTIL-containing microemulsion. The increment in the solvation time is more in case of C-343 compared with other two probe molecules, C-480 and C-153, due to its location at the core of the pool of the RTIL; which confirmed the location of the NPs. (C) 2013 Elsevier B.V. All rights reserved.