Helicene-Based Chiral Macrocycles and Molecular Cages: Synthetic Strategies, Chiroptical Modulation, and Emerging Applications

Macrocycles and molecular cages possess enzyme-like cavities whose size, shape, and functionality can be precisely engineered. Helicenes, characterized by rigid π-conjugated backbones and inherent helical chirality, serve as exceptional scaffolds for constructing highly distorted chiral macrocycles and cages. These supramolecular architectures demonstrate enhanced circularly polarized luminescence (CPL), enantioselective recognition, and efficient guest adsorption. This minireview provides a comprehensive overview of recent advances in helicene-based coordination and covalent strategies, highlighting synthetic methodologies, chiroptical modulation, and emerging applications. Key challenges—including fluorescence quenching in metallacages, synthetic complexity, and limited structural diversity—are critically discussed. We also highlight potential opportunities involving high-emission linkages, dynamic covalent strategies, and stimuli-responsive designs. Collectively, these insights establish a framework for the rational design of helicene-derived macrocycles and three-dimensional cages, paving the way toward the development of advanced chiral functional materials.