To gain FAIR-AR samples, the FAIR metadata for samples are completed with measures to gain accessible and reusable materials/samples: Accessible materials: The first essential step to enable access to the samples is their registration in the Molecule Archive. As soon as the samples are physically deposited and registered in the Molecule Archive, the visibility of the available samples is managed via the website of the Chemotion repository. Scientists interested in re-using the samples can place their sample request directly through the repository's interface (Figure , details added to the SI, chapter 2). A contact form has been set up for each available sample to obtain the chemical compound in the form of a part of the sample. The query automatically transfers the identifier of the sample. A key difference in the notion of "accessible" for data and materials is the following: While access to data can be granted to all interested persons without disadvantage in each case, prioritization must be made for access to the materials. Since the amount of an available chemical compound archived per sample is usually very limited, there must be a consideration of the purposes for which the material should be released. For the Molecule Archive, the decision on whether to release the materials or not is made either based on a material transfer agreement (MTA ) of compound providers with the Molecule Archive (see chapter "reusability") or is decided by the compound providers (and managed by the operators of the repository). The decision is sent to the interested re-users of the chemical compounds and if the material can be sent, the details and conditions for such re-use are