Thiazolo[4,5-d]thiazole—a new domain for potential optoelectronic application

A novel heterocyclic moiety based on thiazolo[4,5-d]thiazole was prepared via a six-step synthesis from butane-2,3-dione. This thiazolothiazole compound was further derivatized to afford either neutral conjugated condensation products or analogous N-alkyl salts. The obtained derivatives represent dipolar structures expressed as A-π-D (push–pull compounds) as well as quadrupolar D-π-A-π-D structures. Both types of compound show intramolecular charge transfer and therefore could be suitable for nonlinear optical applications.