ZINC 15 is a new version of the ZINC database, designed to help researchers find and analyze small molecules for biological targets. It includes over 120 million purchasable "drug-like" compounds, with a quarter available for immediate delivery. ZINC connects purchasable compounds to high-value ones such as metabolites, drugs, and natural products. It offers tools for ligand discovery, including biological activity, chemical property, and commercial availability data. ZINC is freely available at http://zinc15.docking.org. ZINC15 integrates biological activity data from public sources, including ChEMBL, HMDB, and DrugBank, and links compounds to proteins and biological processes. It provides a user-friendly interface for non-experts and is fully programmable for experts. ZINC retains its 3D roots, offering ready-to-dock formats for all molecules. It allows users to search for compounds by chemical similarity, substructure, or specific biological functions. ZINC also supports chemical patterns, rings, and 3D representations for docking. ZINC15 includes features such as chemical search, focused libraries for specific targets, and tools for finding purchasable compounds. It supports multiple formats for downloading data and provides information on the purchasability and biological activity of compounds. ZINC also includes tools for clinical trials, literature links, and API integration for third-party applications. ZINC15 has been improved for experts, enabling them to integrate its features into their applications using the new API. It supports a wide range of chemical properties and provides detailed information on the biological activity of compounds. ZINC is a platform for research tool development, allowing chemists and biologists to answer complex questions without requiring specialized expertise. ZINC15 is a valuable resource for researchers in the field of ligand discovery, providing access to a vast chemical space with detailed annotations and biological information. It supports a variety of search options, including similarity searches, substructure searches, and queries based on biological functions. ZINC15 is continuously updated and includes new vendors and annotated catalogs, improving the availability of purchasable compounds for research.ZINC 15 is a new version of the ZINC database, designed to help researchers find and analyze small molecules for biological targets. It includes over 120 million purchasable "drug-like" compounds, with a quarter available for immediate delivery. ZINC connects purchasable compounds to high-value ones such as metabolites, drugs, and natural products. It offers tools for ligand discovery, including biological activity, chemical property, and commercial availability data. ZINC is freely available at http://zinc15.docking.org. ZINC15 integrates biological activity data from public sources, including ChEMBL, HMDB, and DrugBank, and links compounds to proteins and biological processes. It provides a user-friendly interface for non-experts and is fully programmable for experts. ZINC retains its 3D roots, offering ready-to-dock formats for all molecules. It allows users to search for compounds by chemical similarity, substructure, or specific biological functions. ZINC also supports chemical patterns, rings, and 3D representations for docking. ZINC15 includes features such as chemical search, focused libraries for specific targets, and tools for finding purchasable compounds. It supports multiple formats for downloading data and provides information on the purchasability and biological activity of compounds. ZINC also includes tools for clinical trials, literature links, and API integration for third-party applications. ZINC15 has been improved for experts, enabling them to integrate its features into their applications using the new API. It supports a wide range of chemical properties and provides detailed information on the biological activity of compounds. ZINC is a platform for research tool development, allowing chemists and biologists to answer complex questions without requiring specialized expertise. ZINC15 is a valuable resource for researchers in the field of ligand discovery, providing access to a vast chemical space with detailed annotations and biological information. It supports a variety of search options, including similarity searches, substructure searches, and queries based on biological functions. ZINC15 is continuously updated and includes new vendors and annotated catalogs, improving the availability of purchasable compounds for research.