2-Mercaptosuccinic acid (MS) is an important and versatile substance for diverse fields of applications of which the most significant are surveyed in this article. Biological, chemical, and physical properties of MS as well as the knowledge of its synthesis and microbial degradation are illustrated. In addition, exemplary structural analogs of the organic sulfur compound are commented. The key application of MS in nanotechnology is discussed in detail with particular emphasis on quantum dots (nanocrystals) and self-assembled monolayers in combination with gold or silver. Furthermore, some medical and pharmaceutical applications are given, inter alia in bioimaging, as a nanocarrier, and with regard to the antimicrobial activity of MS-silver and MS-gold nanoparticles. Moreover, biological and chemical applications of MS are exemplified: the thiol compound can serve as an inhibitor for glutathione peroxidase, or the toxicity of substances can be increased due to the presence of MS in the respective cells or tissues. In the field of cosmetics, MS is widely utilized as a reducing agent for numerous products as explained in this article. Additionally, the microbial utilization of MS as a carbon and energy source for growth is elucidated in-depth, providing insight into different catabolic mechanisms.