Indigoid photoswitches comprise a class of chromophores that are derived from the parent and well-known indigo dye. Different from most photoswitches their core structures absorb in the visible region of the spectrum in both isomeric states even without substitutions, which makes them especially interesting for applications not tolerant of high-energy UV light. Also different from most current photoswitching systems, they provide highly rigid structures that undergo large yet precisely controllable geometry changes upon photoisomerization. The favorable combination of pronounced photochromism, fast and efficient photoreactions, and high thermal bistability have led to a strongly increased interest in indigoid photoswitches over the last years. As a result, intriguing applications of these chromophores as reversible triggering units in supramolecular and biological chemistry, the field of molecular machines, or smart molecules have been put forward. In this Account current developments in the synthesis, mechanistic understanding of light responsiveness, advantageous properties as phototools, and new applications of indigoid photoswitches are summarized with the focus on hemithioindigo, hemiindigo, and indigo as key examples.

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靛蓝光电开关：可见光响应分子工具

靛类光开关包括一类发色团，其发自母体和众所周知的靛蓝染料。与大多数光电开关不同，它们的核心结构即使在没有取代的情况下，在两种异构状态下也能吸收光谱的可见光区域，这使它们对于不耐高能紫外光的应用尤为有趣。它们也不同于大多数当前的光开关系统，它们提供了高度刚性的结构，这些结构在光异构化后会经历较大但可精确控制的几何形状变化。在过去的几年中，显着的光致变色，快速有效的光反应以及高热双稳性的良好组合，引起了对靛类光开关的强烈兴趣。因此，这些生色团作为可逆触发单元在超分子和生物化学，分子机器或智能分子领域中的有趣应用已被提出。在这个帐户中，总结了当前的合成技术发展，对光响应性的机械理解，作为光工具的有利性能以及靛类光开关的新应用，重点是半硫靛蓝，半靛蓝和靛蓝作为关键实例。