The Chemistry of Subphthalocyanines: Synthetic Strategies for their Axial, Peripheral, and Remote Postfunctionalization

Subphthalocyanines (SubPcs) currently hold a privileged position among the most versatile scaffolds for the design of π‐conjugated materials. In this context, the remarkable chemical tunability of these macrocycles has played a pivotal role, which has given rise to a unique and rich chemistry over the past two decades. Most recently, postfunctionalization strategies have been successfully applied at the axial ligand, the peripheral positions, and remote sites from the SubPc core. However, each of these approaches requires careful selection of reaction conditions, considering the high sensitivity of SubPcs against strong nucleophiles. In this review, a comprehensive overview of the full synthetic toolbox available for the postfunctionalization of SubPcs is provided. Special emphasis is placed on reaction conditions, functional group tolerance, and structural scope, as well as mechanistic insights when available. Finally, the main synthetic challenges that remain to be addressed in order to fully exploit the potential of SubPc chemistry are outlined. Altogether, this review aims to serve not only as a practical guide for chemists working in the field, but also as an inspiration for future developments in the chemistry of curved π‐conjugated systems.