A Review on Microwave‐Assisted Synthesis of Fused N‐Containing Bioactive Heterocyclic Molecules

ABSTRACT N‐heterocyclic compounds (NHCs) play a pivotal role in organic, industrial, and medicinal chemistry owing to their structural diversity, electronic tunability, and broad spectrum of biological activities. Five‐, six‐, and seven‐membered fused N‐heteroaromatic systems are especially valuable, serving as key frameworks in drug discovery, catalysis, and functional materials. To meet the growing demand for efficient and sustainable synthetic methods, unconventional approaches have been explored, with microwave‐assisted organic synthesis (MAOS) emerging as one of the most powerful and versatile techniques. This review focuses exclusively on microwave‐enabled routes cyclocondensations, cycloadditions, multicomponent reactions, and metal‐catalyzed cross‐couplings such as Heck and Sonogashira for constructing fused NHCs. Unlike previous broad surveys of MAOS, this work emphasizes green chemistry metrics, structure activity relationship insights, and performance comparisons with conventional heating, covering literature from 2005 to 2024. The reported microwave protocols consistently demonstrate remarkable efficiency, delivering products in high yields (up to 95%) with dramatically reduced reaction times, often under 10 min. Many processes also enable solvent‐free or environmentally benign conditions, underscoring the sustainability advantages of MAOS. Overall, the review highlights how microwave methodologies not only streamline access to complex heterocyclic scaffolds but also facilitate the development of bioactive molecules with antimalarial, anticancer, antiviral, and other therapeutic potential.