Tuning Aggregation in Liquid‐Crystalline Squaraine Chromophores

For a series of novel hydroxy anilino squaraines (SQ), separated via short flexible spacers from bulky dendrons, hexagonal columnar (Colhex) liquid‐crystalline (LC) phase behavior is detected. The optical properties of these SQ systems, designed for melting below 80 °C, very low for SQ systems, are found to be determined by the LC structures which in turn are governed by volume and steric effects of the dendrons affecting the temperature‐dependent interplay between monomeric species and H‐aggregates in the LC state, ultimately responsible for the optical properties. Experimental results are corroborated by self‐consistent field theory (SCFT) as well as time‐dependent density functional theory calculations (TD‐DFT). The results demonstrate a new strategy for dynamically tuning aggregates and optical properties for the prescriptive functionalization of the LC SQ materials and with potential for other aggregating systems.