Covalent Functionalization of 2D Semiconductors: A Roadmap to Advanced Electronic Devices

ABSTRACT Two‐dimensional (2D) semiconductors have emerged as key components for next‐generation electronic, optoelectronic, and sensing technologies. Accordingly, there has been growing interest in tuning their properties to enhance functionality and enable multiple capabilities within the same material system. While early approaches relied on thickness control or electrostatic gating, molecular functionalization has evolved into a powerful alternative, allowing direct chemical modification at the atomic scale. Molecular decoration has already offered precise control over chemical reactivity, interfacial processes, environmental stability, and charge transport, opening new pathways for the application of 2D materials in modern technologies. This review evaluates the fundamental principles and recent advances in the covalent functionalization of 2D semiconductors. Defect‐mediated, basal‐plane, and edge‐specific strategies are discussed, highlighting their impact on electronic and optical behaviour as well as on device performance. Emerging applications in electronics, sensing, flexible systems, and adaptive or neuromorphic devices are examined. Finally, the key challenges related to scalability, stability, and process integration are addressed, and future directions and opportunities are outlined with a specific focus on data‐driven molecular design and the engineering of multifunctional and stimuli‐responsive systems making use of sustainable chemistry strategies.