Carbon-Di(indolin-3-one)methene: A BODIPY-Analogue Chromophore Exhibiting Photothermal Conversion

An imidazole-induced divergent condensation of 1-acetyl-3-indolinone affords both conventional BOINPY precursors and a previously unrecognized chromophore, carbon-di(indolin-3-one)methene (CDIIN3OM). This carbon-bridged π-conjugated scaffold departs from classical dipyrrin systems and can be converted into BF₂-coordinated analogues. The resulting dyes exhibit broad visible-to-near-infrared absorption, weak fluorescence, and photothermal conversion. Density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations revealed the electron-withdrawing properties of imidazole and the relationship between structure and properties. These findings establish CDIIN3OM as a new chromophore core and demonstrate a reaction-based strategy for scaffold discovery.