Angewandte Chemie International Edition
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Electrochemiluminescence involves the generation of light via electrochemical reactions and has recently shown utility for single-cell imaging. To further develop this novel imaging platform, it is necessary to produce readily available dyes that photoluminesce and electrochemiluminesce in the near-infrared region to limit absorption by biological tissue. To address this need, we prepared a boron difluoride formazanate dye that exhibits near-infrared photoluminescence and electrochemiluminescence in two straightforward synthetic steps. Examination of its solid-state structure suggests that the N-aryl substituents have significant quinoidal character, which narrows the S1-S0 energy gap and leads to near-infrared absorption and photoluminescence. Electrochemical properties were probed using cyclic voltammetry and revealed four electrochemically reversible waves. Electrochemiluminescence properties were examined in the presence of tri-n-propylamine, leading to maximum intensity at 910 nm, at least 85 nm (1132 cm‒1) red-shifted compared to all other organic dyes. This work sets the stage for the development of future generations of dyes for emerging applications, including single-cell imaging, that require near-infrared photoluminescence and electrochemiluminescence.