C3h‐symmetric and Cs‐symmetric Triformyl Triindolo‐Truxenes: Synthesis and Properties

C3h‐symmetric and Cs‐symmetric triformyl triindolo‐truxenes with different substitution positions of formyl groups were developed by two synthetic strategies. Direct formylation of triindolo‐truxene using Rieche formylation produced C3h‐symmetric and Cs‐symmetric triformyl triindolo‐truxenes in one‐pot. Four‐step synthesis starting from truxene gave a carbonyl‐modified C3h‐symmetric triformyl triindolo‐truxene. The optical and electrochemical properties of triformyl triindolo‐truxenes were modulated by changing the substitution positions of formyl groups and introducing carbonyl groups into molecules. The Cs‐symmetric triformyl triindolo‐truxenes exhibited red‐shifted absorption and emission, higher HOMO levels, and narrower HOMO‐LUMO gaps than those of C3h‐symmetric analogues. Furthermore, carbonyl‐modified C3h‐symmetric triformyl triindolo‐truxene showed the longest absorption and emission and narrowest HOMO‐LUMO gap among its analogues. The assembly of triformyl triindolo‐truxenes in single crystals and solution was investigated. This work provides valuable building blocks for constructing supramolecular architectures and adds new aspects of reactivity and structure‐property relationship of triindolo‐truxene. C3h‐symmetric and Cs‐symmetric triformyl triindolo‐truxenes were developed. Their photophysical and electrochemical properties as well as molecular aggregation can be tuned by different substitutions of butyl, formyl, or carbonyl groups to triindolo‐truxene skeletons.