The dielectric permittivity (') and dielectric loss ('') for dilute solutions of acetone (CH3COCH3) in benzene solution have been measured at 9.88 GHz for different temperatures (25, 30, 35 and 40oC) by using standard microwave techniques. Using the single frequency concentration variational method; the dielectric relaxation time () and dipole moment (μ) at various temperatures have been calculated. It is observed that dielectric relaxation process can be treated as the rate process, just like the viscous flow. Based on above microwave absorption data, monomer structure of acetone in benzene solution has been inferred. The presence of solute-solvent molecular associations in benzene solution has not been proposed. Energy parameters (H, F, S) for dielectric relaxation process of acetone in benzene at different temperatures (25, 30, 35 and 40oC) have been calculated and compared with the corresponding energy parameters (H, F, S) of viscous flow process.