No restrictions or limitations apply to using and reusing the dataset. Everyone can this dataset as a standard benchmark set for the evaluation of the performance of their OCSR tools. The dataset includes a wide range of chemical structures and represents a much larger chemical space. The structures were drawn by various individuals to ensure the diversity of drawing styles. The main limitation is caused by the molecular weight filter (< 1500 Da) as it excludes certain molecules like big macrocycles, proteins or artificial polymers. Additionally, markush structures are not represented.