From Ions to Biomolecules and Beyond: Versatile Starburst Triphenylamine-Based Scaffolds as Multifunctional Tools for Advanced Sensing Applications.

Efficiently converting chemical interactions into tunable signals remains a key challenge in modern materials chemistry. Among the designs that have risen to meet this need, triphenylamine (TPA) has emerged as an exceptionally versatile platform for high-performance molecular sensing. It is a nitrogen-centered organic scaffold recognized as a benchmark framework in materials chemistry owing to its propeller-shaped geometry, remarkable electronic characteristics, and excellent functional adaptability. Although historically utilized in organic electronics, solar cells, and electrochromic systems, TPA derivatives have recently gained significant attention in molecular sensing applications. Their inherent photostability, strong electron-donating capacity, and tunable π-conjugation enable efficient translation of molecular recognition events into well-defined optical signals. Modern molecular designs exploiting aggregation-induced emission (AIE), intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and excited-state intramolecular proton transfer (ESIPT) processes have yielded highly sensitive "turn-on" and "turn-off" probes. These developments have substantially broadened the sensing scope of TPA-based systems toward toxic inorganic anions, biologically relevant metal ions, nitroaromatic explosives, and environmentally significant bio- and other diverse analytes. This review consolidates recent advancements in TPA-derived sensing platforms, emphasizing their selectivity, various analyte classes, and emerging trends to inspire future innovation in this rapidly evolving field.