Synthesis and Photophysical Properties of Star‐Shaped Triphenylamine Trimers Functionalized With BODIPY and Subphthalocyanine Chromophores

ABSTRACT This work reports the synthesis, characterization, and solution photophysical properties of para ‐trisubstituted triphenylamine (TPA) derivatives that preserve the threefold symmetry around the central nitrogen atom. By functionalizing the TPA core with three units of one of two representative boron‐containing chromophores—BODIPY and subphthalocyanine (SubPc)—we directly compare how chromophore identity and molecular topology determine the optical response of the resulting star‐shaped architectures. Whereas neither family exhibits significant solvatochromism in absorption, their fluorescence is strongly governed by both the solvent and the molecular architecture. The SubPc‐based trimer undergoes efficient fluorescence quenching in all but the least polar solvent studied ( Φ ≤ 2%, partially restored to 10% in methylcyclohexane), consistent with an effective intramolecular excited‐state deactivation pathway. In contrast, the BODIPY‐based trimer remains strongly quenched in polar media while developing a new red‐shifted emission band ( λ em = 606 nm) with a markedly enhanced fluorescence quantum yield ( Φ = 26%) in toluene. Comparison with the corresponding monomeric reference compounds demonstrates that these distinctive photophysical properties arise primarily from the threefold star‐shaped architecture rather than from the intrinsic optical properties of the individual chromophores. These findings establish molecular topology as an effective design parameter for tuning excited‐state dynamics in multichromophoric TPA‐based systems.