“…Of the developed solvent systems, deep eutectic solvents (DESs) have been recognized as an emerging class of functional solvents for the dissolution of lignocellulosic components. Generally, DESs are composed of two components via the hydrogen bonding interaction to generate a eutectic mixture, and the two components are hydrogen-bond donor (HBD) and hydrogen-bond acceptor (HBA), respectively. , The DESs designed by selecting suitable HBDs and HBAs of different properties could enable them to possess various unique advantages, e.g., strong solvation ability, good designability, low cost, facile preparation, high biocompatibility, etc. − These characteristics of DESs promote the continually growing interest in constructing efficient DESs to dissolve cellulose, hemicellulose, or lignin. − As reported, DESs can be defined as the mixture of two or more pure compounds with a eutectic point temperature below that for an ideal liquid mixture, showing significantly negative deviations from ideality . More importantly, the composition of DESs should be in a certain range, not just in a fixed stoichiometric proportion .…”