Room-temperature ionic liquids (RTILs), N,N,N-trimethyl-N-propyl ammonium bis(trifluoromethanesulfonyl) imide ([N-3111][Tf2N]), were substituted for polar water and formed nonaqueous microemulsions with cyclohexane by the aid of nonionic surfactant TX-100. The phase behavior of the ternary system was investigated, and microregions of [N-3111][Tf2N]-in-cyclohexane (IL/O), bicontinuous, and cyclohexane-in-[N-3111][Tf2N] (O/IL) were identified by traditional electrical conductivity measurements. Dynamic light scattering (DLS) revealed the formation of the IL microemulsions. The FUR study of O-H stretching band of TX100 also supports this finding. The dynamics of solvent and rotational relaxation have been investigated in [N-3111][Tf2N]/TX100/cyclohexane microemulsions using steady-state and time-resolved fluorescence spectroscopy as a tool and coumarin 480 (C-480) as a fluorescence probe. The size of the microemulsions increases with gradual addition of [N-3111][Tf2N], which revealed from DLS measurement. This leads to the faster collective motions of cation and anions of [N-3111][Tf2N], which contributes to faster solvent relaxation in microemulsions.