Structural and thermodynamic properties of cellulose solutions in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIMAc) and its binary mixtures with N,N-dimethyl formamide (DMF) are studied by small-angle X-ray scattering (SAXS). These measurements indicate molecular dissolution of the cellulose chains without any significant aggregation. The power-law relationships of the evaluated correlation length and osmotic modulus to concentration exhibit exponents of -0.76 and 2.06 for EMIMAc and -0.80 and 2.14 for DMF/EMIMAc solvent mixture, respectively. Thus, these solvents can be considered to be good solvents for cellulose. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017, 55, 888-894