Olfactory perception occurs when odorous molecules activate specialized sensory receptors on neurons. Smell recognition relies on a combinatorial activation code of odorant receptors (ORs), though the rules governing ligand recognition remain poorly understood. Focusing on the cornerstone of smell perception, the olfactory receptors (ORs), we introduce M2OR[1], a database featuring 75,050 experimental measurements across 1,257 OR sequences from 11 species. This database is carefully curated to ensure accurate molecular representation, including the differentiation of isomers essential for olfactory recognition. It also provides detailed information on biological assays, such as cell lines, readout methods, and G-protein types. An analysis of OR-molecule interactions reveals that 83% of results are consistent across experimental conditions, with most ligands exhibiting micromolar activity. For human ORs, 88% remain to be deorphanized. Additionally, the study estimates OR recognition range and proposes a framework for comparing future machine learning models predicting OR-odorant interactions[2]. [1] M. Lalis, M. Hladiš, S. A. Khalil, L. Briand, S. Fiorucci, J. Topin. M2OR: a database of olfactory receptor–odorant pairs for understanding the molecular mechanisms of olfaction, Nucleic Acids Research, 2024, https://doi.org/10.1093/nar/gkad886. [2] M. Lalis, M. Hladiš, S. A. Khalil, C. Deroo, C. Marin, M. Bensafi, N. Baldovini, L. Briand, S. Fiorucci, J. Topin*. A status report on human odorant receptors and their allocated agonists, Chemical Senses 49, 2025 : bjae037.