A comprehensive set of molecules for CSP method validation was compiled. The dataset is divided into three tiers following definitions established by previous CCDC CSP blind tests. The first tier consists of mostly rigid molecules up to 30 atoms. The second tier consists of small druglike molecules with around two to four rotatable bonds, and up to approximately 40 atoms. The third tier is composed of large drug-like molecules with five to ten rotatable bonds, usually containing 50 to 60 atoms. Additional tiers will be defined in the future as the complexity of CSP targets increase. The entire collection of test molecules is shown in Figure .