PROJECT SUMMARY (DEVELOPMENT CORE) The goal of the NYU Collaborative Center in Children’s Environmental Health Research and Translation (CEHRT) Development Core is to stimulate promising research early in the translational phases that generate preliminary data (T1–T2), and develop and test new interventions, prevention strategies and communication strategies (T3–T4). The Development Core will launch a “Catalyst Program” to provide catalytic support for innovative pilots that will generate new and emerging children’s environmental health (CEH) research projects, facilitate local and national collaborations in CEH, and support mentored investigator development pilot project and enrichment opportunities for junior scientists at NYU and nationally. The Catalyst Program will center on nurturing the career development of early stage investigators from across the country through strong mentorship and interactive, virtual platforms our team has successfully used, especially with junior scientists from communities underrepresented in health research. The Development Core will also work in tandem with the Translation Core to prepare promising Development Core Catalyst pilot awardees to further “real-life” application with additional opportunities for pilot funds and other support from the Translation Core. The Core’s Specific Aims are to: 1) Stimulate promising and innovative interventions to reduce hazardous exposures in children from pregnancy, early childhood, and adolescence. 2) Provide tailored mentorship using a spectrum approach to mentoring for early stage investigators and support pilot project monitoring and progress. 3) Design and conduct a translation plan to disseminate Catalyst Program pilot study findings and best practices in investigator development. The Development Core will apply the Reach Effectiveness Adoption Implementation and Maintenance (RE-AIM) framework to identify best practices to develop investigators and their research, and support mentees’ capacity to translate research findings into action. Through these efforts, the Development Core will cultivate a cadre of the next generation of CEH research leaders, trained in translational research methods that can substantially improve population health. These funds will catalyze timely and innovative translational research; enabling investigators to both gather preliminary data for larger, extramurally funded studies and, through mentored experiences, contribute to the research independence of junior scientists and their understanding of research translation. The Core will also establish reinforcing mechanisms to support a national peer and senior mentor resource to stimulate translational CEH research, fostering collaborations across NIEHS networks.