Synthetic Diversification of Isoquinolin‐1(2 <i>H</i> )‐Ones: Emerging Strategies and Methodological Advances

ABSTRACT Isoquinolin‐1(2 H )‐ones represent an important class of nitrogen‐containing heterocycles widely found in natural products and pharmacologically active compounds. Recent developments in their functionalization have enabled the construction of structurally diverse and bioactive derivatives through selective halogenation and C–X (X = S, N) bond formation. This review summarizes key methodologies, including transition‐metal‐catalyzed processes and metal‐free radical‐based approaches. Adopting sustainable techniques such as visible‐light photocatalysis, electrochemical methods, and solvent‐free protocols has significantly improved the environmental profile of these transformations. These advances offer versatile and efficient tools for synthesizing functionally rich isoquinolone derivatives with broad relevance in medicinal chemistry and materials science.