Dienes are versatile substrates in transition metal-catalyzed reactions due to their abundance, ease of synthesis, and unique stereoelectronic properties. This review highlights recent advances in diene functionalization, emphasizing their role in synthesizing complex, bioactive molecules. Over the past decade, significant progress has been made in developing new methodologies for diene-based transformations, including hydrofunctionalization, difunctionalization, heteroannulation, and cycloaddition. Transition metal catalysis enables selective functionalization of dienes, offering efficient and atom-economical approaches for constructing complex molecular structures. Key developments include the synthesis of enantioenriched allylic ethers, amines, and alcohols through various catalytic systems, as well as the generation of diverse heterocycles and cycloalkanes. The review also discusses challenges and opportunities in expanding the scope of diene reactions, demonstrating their importance in both academic research and industrial applications.Dienes are versatile substrates in transition metal-catalyzed reactions due to their abundance, ease of synthesis, and unique stereoelectronic properties. This review highlights recent advances in diene functionalization, emphasizing their role in synthesizing complex, bioactive molecules. Over the past decade, significant progress has been made in developing new methodologies for diene-based transformations, including hydrofunctionalization, difunctionalization, heteroannulation, and cycloaddition. Transition metal catalysis enables selective functionalization of dienes, offering efficient and atom-economical approaches for constructing complex molecular structures. Key developments include the synthesis of enantioenriched allylic ethers, amines, and alcohols through various catalytic systems, as well as the generation of diverse heterocycles and cycloalkanes. The review also discusses challenges and opportunities in expanding the scope of diene reactions, demonstrating their importance in both academic research and industrial applications.