Physicochemical studies on the effect of protic ionic liquid (PIL) on monomer unit of cellulose are needed to understand the structural interactions taking place between carbohydrate polymers and ILs. Therefore, we have studied the volume and enthalpy of dilution of D(+)-glucose and D(+)-xylose in water and in (0.10, 0.15, 0.20, and 0.25) mol kg(-1) aqueous solutions of newly synthesized N-methyl-2-pyrrolidonium formate; [NMPI[For] and N-methyl-2-pyrrolidonium propionate; [NMPI[Pro] at T=(288.15-318.15) K. Further, nuclear magnetic resonance spectroscopy (NMR) has also been employed to understand the nature of interactions occurring in ternary solutions (PIL water + monosaccharides). The dominance of hydrophobic type of interactions between monosaccharides and PILs in aqueous solutions has been observed. The results obtained from thermophysical and spectroscopic techniques complement each other and can be used to understand key factors determining the cellulose dissolution process. (C) 2016 Elsevier B.V. All rights reserved.