Recent progress in ionic liquid-catalyzed multicomponent reactions: a green and sustainable approach to organic synthesis in line with the UN SDGs

Traditional synthetic methods frequently rely on hazardous reagents, consume significant energy, and generate considerable amounts of chemical waste, thereby posing serious environmental and safety concerns. The growing emphasis on sustainable and eco-friendly chemical developments has propelled the development of multicomponent reactions (MCRs) as efficient synthetic tools in modern organic chemistry. Ionic liquids (ILs) represent a significant advancement among green catalysts, offering versatility, recyclability, and environmental friendliness. Their tunable physicochemical properties and dual role as solvents and catalysts enhance their applicability in various chemical processes. This review discusses the progress in ionic liquid-catalyzed multicomponent reactions (MCRs) for synthesizing diverse heterocyclic frameworks, such as pyridines, pyrimidines, pyrazoles, triazoles, xanthenes, indoles, indazoles, imidazoles, and several pyran and chromene derivatives. This review provides a full summary of the progress made in ionic liquid-catalyzed one-pot multicomponent reactions from 2020 to 2025. It focuses on how these reactions can be used to make a diverse array of heterocyclic scaffolds, bio-active molecules, and complex organic frameworks. The catalytic performance, reaction mechanisms, substrate scope, and green chemistry metrics of various IL systems-such as task-specific ILs, supported IL phases, and magnetic ionic liquid composites-are critically discussed.