Temperature-dependent fluorescence anisotropies of a nonpolar solute 9-phenylanthracene (9-PA) have been measured in 1-alkyl-3-methylimidazolium-based ionic liquids with anions such as bis(trifluoromethylsulfonyl)imide ([Tf₂N⁻]), tris(pentafluoroethyl)trifluorophosphate ([FAP⁻]), tetrafluoroborate ([BF₄⁻]), and hexafluorophosphate ([PF6⁻]) to find out if the organized structure of the ionic liquid has a bearing on solute rotation. Analysis of the experimental data using the Stokes− Einstein−Debye hydrodynamic theory indicates that there is no significant variation in the solute−solvent coupling constants (C_obs) with an increase in the length of the alkyl chain on the imidazolium cation for the ionic liquids with [Tf₂N⁻] and [FAP⁻] anions. However, in the case of ionic liquids with [BF₄⁻] and [PF₆⁻] anions, the rotation of 9-PA for a given viscosity at constant temperature becomes progressively faster and Cobs decreases by a factor of 2.4 from ethyl to octyl derivatives. Quasihydrodynamic theories of Gierer−Wirtz and Dote−Kivelson−Schwartz could not account for the significant decrease in the C_obs values. The observed behavior has been rationalized in terms of the organized structure of the ionic liquids having [BF₄⁻] and [PF₆⁻] anions, which results as a consequence of the high charge-to-size ratio of these anions compared to [Tf₂N⁻] and [FAP⁻].