Natural deep eutectic systems (NADES) which have gained increasing scientific interest and the attention of the scientific community is beginning to be directed towards understanding the characteristics of these liquids that make them extremely particular. NADES are essentially formed through hydrogen bond interactions, between a hydrogen-bond donor compound and a hydrogen bond acceptor compound. The arrangements of different molecules that can constitute different NADES are estimated to be around 106 possible combinations (in the case of only binary mixtures). This article aims to present NADES and their applications, as well as describe their main characteristics in terms of their physicochemical properties. In addition, new developments in relation to the state of the art on the exploitation of their properties as solvents in applications such as extraction, (bio)catalysis and synthesis of pharmaceuticals, agrochemicals, functional materials or other high-added value substances with be discussed. Advances in different research areas have been notable in the last 10 years, boosting fundamental and basic research on NADES.

Funding Information: This work has received funding from the European Research Council through grants ERC-CoG-725034, ERC-PoC-101067844, ERC-PoC-101138403. This work was financed by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P., under the scope of the project UID/50006/2023 of the Associate Laboratory for Green Chemistry-LAQV REQUIMTE We also thank the Foundation for Science and Technology (FCT) for funding to the Coimbra Chemistry Centre-Institute for Molecular Sciences (CQC-IMS) via projects; UIDB/ 00313/2020| UIDP/00313/2020. Publisher Copyright: © 2025, TeknoScienze. All rights reserved.