Ionic liquids (ILs) have emerged as versatile and environmentally benign alternatives to conventional organic solvents, offering unique physicochemical properties such as negligible vapour pressure, wide liquid-state temperature range, high thermal stability, and tunable polarity. These attributes have made ILs highly effective media and catalysts for the synthesis of structurally diverse heterocyclic compounds such as imidazole, thiazole, pyrazole, benzimidazole, etc. which continue to serve as fundamental scaffolds in pharmaceuticals, agrochemicals, dyes, and advanced functional materials. This comprehensive review critically examines recent developments in the ionic liquid–mediated synthesis of heterocyclic frameworks, emphasizing the versatile roles of ILs as solvents, catalysts, co-catalysts, and reaction modifiers. The special emphasis is placed on IL-assisted strategies for constructing nitrogen, oxygen, and sulphur-containing heterocyclic derivatives, along with comparisons to traditional synthetic approaches in terms of efficiency, selectivity, yield, and sustainability. The review also discusses mechanistic insights, the influence of IL structure on reactivity, and the integration of ILs with microwave, ultrasound, and metal-free methodologies. Furthermore, challenges such as recyclability, toxicity, cost, and scale-up limitations are critically evaluated. Overall, this work underscores the growing significance of ionic liquids as green and powerful platforms for advancing heterocyclic chemistry and outlines future research directions for their broader application in sustainable organic synthesis.