Synthesis of Indolo[3,2-b]carbazole-Based Boron Complexes with Tunable Photophysical and Electrochemical Properties

New synthetic strategies were developed for the synthesis of indolo-pyridine boron difluoride (IPBD) dyes and antiladder-type π-conjugated dyes based on the pyridine/pyrazine-indolocarbazole (ICZ) structures. The photophysical and electrochemical properties of the dyes were measured in solution, solid state, and thin films and rationalized by theoretical calculations. Interestingly, these properties of the dyes can be tuned in a wide range using the developed chemical route. For example, the absorption range and fluorescence color of the dyes in solution and solid state and the HOMO-LUMO energy gaps were tuned by structure modulations. The absorption properties of those new boron complexes cover most of the UV-visible-NIR spectrum. Therefore, this appealing tunability feature makes these new types of dyes very promising candidates for their further use in functional material development.