Liquid-crystalline semiconductors: From molecular ordering to programmable electronic function

Liquid-crystalline semiconductors combine electronic functionality with molecular mobility, anisotropic order, and stimulus-responsive phase behavior. Initially used to improve charge transport through π–π stacking, reduced disorder, and macroscopic alignment, they are increasingly viewed as ordered soft materials whose phase, director orientation, interfacial structure, ionic distribution, and relaxation dynamics can be actively controlled. Thermotropic systems reorganize through temperature-dependent mesophase transitions, whereas lyotropic systems develop concentration-, solvent-, and flow-dependent order before solidification. This review examines the progression from mobility-oriented materials to adaptive and reconfigurable ordered platforms across small-molecule, conjugated-polymer, mixed ionic–electronic, and bio-derived liquid-crystalline systems. We connect molecular design and processing history to hierarchical structure, interfaces, and electronic, ionic, optical, and adaptive device responses. We further assess quantitative order–transport correlations, scalable alignment, reproducibility, operational stability, and the distinction between reversible dynamics and degradation. These considerations define opportunities for adaptive organic electronics, bio-integrated devices, and material-based information processing.