N-Carboxyanhydride-Derived Polypeptides as Programmable Platforms for Hierarchical Chiral Assembly and Chiroptical Materials

N-carboxyanhydride (NCA)-derived polypeptides are programmable platforms for hierarchical chiral assembly and chiroptical materials. Their controlled stereochemistry, chain length, architecture, and functionality regulate secondary structures such as α-helices and β-sheets, which further guide assembly into nanostructures, liquid-crystalline phases, and bulk ordered materials. This review summarizes how polymer structure and secondary conformation govern chiral assembly, chirality transfer, and chiroptical responses, including circular dichroism, induced circular dichroism, and circularly polarized luminescence. Recent examples of liquid-crystalline polypeptides, homopolypeptide nanotoroids, chromophore co-assemblies, and phosphorescent aggregates are discussed. Challenges and opportunities in structural diversity, performance, and block copolypeptide platforms are also highlighted.