A Bifunctional Electrochromic/Electrofluorochromic Ionic Liquid Enables Displayable Smart Windows with High Energy Efficiency

Abstract The integration of display functionality into electrochromic (EC) smart windows offers a promising avenue for enhancing energy efficiency, urban aesthetics, and public interaction in modern high‐rise buildings. However, their development has been impeded by the limited choice of electroactive materials with effective solar spectral modulation, high optical contrast, and visible fluorescence. In this study, a bifunctional electrochromic/electrofluorochromic (EC/EFC) ionic liquid containing triphenylamine, carbazole, and imidazole moieties (EEIL) is designed and synthesized. Displayable smart windows are constructed using a pixel confinement strategy and exhibits impressive programmed reflective/emissive dual‐modal display performance with high optical contrast across diverse lighting environments. Notably, the device exhibits exceptional optical/thermal management characteristics within the solar radiation spectrum range, achieving an energy efficiency of 13.44% of the total energy consumption. The synergistic integration of dual‐modal display capabilities with efficient optical and thermal management has contributed to the development of sustainable and interactive urban environments.