Synthesis and Characterization of Novel Bifunctional Hemithioindigo Chromophores SteinleWencke Rück-BraunKarola 2002 General methods for the synthesis of novel bifunctional hemithioindigo (HT) compounds, e.g., ω-amino acid derivatives, are presented. The photochromic properties of the photoswitches have been characterized by UV−vis and <sup>1</sup>H NMR spectroscopy.