The National Institutes of Health (NIH) is offering a funding opportunity titled "Discovery of in vivo Chemical Probes for the Nervous System (R01 Clinical Trial Not Allowed)" aimed at supporting research into novel small molecules that can enhance the understanding of biological processes related to mental health, aging, addiction, and eye diseases. Applicants are expected to have validated starting compounds for chemical optimization and bioassays for testing new analog compounds, with a focus on projects that provide insights into disease-related biological targets and mechanisms. This grant opportunity is open to a wide range of eligible applicants, including higher education institutions, nonprofit organizations, and foreign entities, with key application dates starting from January 5, 2024, and a closing date of January 7, 2027. For further inquiries, interested parties can contact NIH Grants Information at grantsinfo@nih.gov, and additional details can be found at the provided link: https://grants.nih.gov/grants/guide/pa-files/PAR-24-088.html.