Near‐Infrared Photoluminescence and Electrochemiluminescence from a Remarkably Simple Boron Difluoride Formazanate Dye

Abstract A boron difluoride formazanate dye that exhibits near‐infrared photoluminescence and electrochemiluminescence was produced via a straightforward two‐step synthesis. Examination of its solid‐state structure suggested that the N ‐aryl substituents have significant quinoidal character, which narrows the S 1 –S 0 energy gap and leads to the unique optoelectronic properties observed. Cyclic voltammetry studies revealed two oxidation waves and two reduction waves that were electrochemically reversible. 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.