We have investigated the change in the interaction of solute and the ionic liquid-DMSO mixture with the extent of dissolution of cellulose. This study aims to provide an insight into the dissolution of cellulose in ionic liquid-DMSO mixtures in terms of photophysical aspects. Although the rheology and viscoelastic properties of ionic liquid-DMSO-cellulose mixtures are well studied in the early literature, there is a lack of photophysical investigation. For this reason, we have taken two oppositely charged but structurally similar solute, fluorescein sodium salt (Fl-Na) and rhodamine 6G (R6G), to investigate their rotational and translational dynamics in the mixture. Analysis of the time-resolved fluorescence anisotropy data using the Stokes-Einstein-Debye (SED) theory suggests that the rotational relaxation times of the solutes follow near stick hydrodynamics in absence of cellulose. The solutes experienced a strong interaction in pure DMSO and with the increasing concentration of BmimCl, the specific interaction between the solvent and the solute decreases as indicated in decreasing C_obs values. While in presence of cellulose, the solutes follow near slip hydrodynamics in low BmimCl concentration but at higher concentration, the specific interaction increases. From the temperature-dependent anisotropy, we have observed that both R6G and Fl-Na follows the super-stick trend, and with increasing temperature specific interaction between the solute and solvent increases. On the other hand, in presence of cellulose, their rotational reorientation times appear close to the slip boundary condition at low temperature, and with increasing temperature, it approaches close to the stick boundary. Fluorescence Correlation Spectroscopy (FCS) indicates the presence of structural heterogeneity in the BmimCl-DMSO mixture formed due to the segregation of the hydrophobic chain of the ionic liquid. Therefore, the experimental results of this work suggest that the dissolution of cellulose modulates the dynamics of the solutes in ionic liquid–DMSO mixtures.