Abstract This special issue celebrates the 25th Anniversary of the Centre of Super‐Diamond and Advanced Films (COSDAF) at the City University of Hong Kong (CityUHK), coinciding with the 30th anniversary of CityUHK. It showcases the research contributions of both current staff and former members of COSDAF. Established in 1998 by Prof. Shuit‐Tong Lee, COSDAF serves as a university‐level research center, bringing together academic experts from various disciplines focused on semiconductor nanomaterials, nano‐organic light‐emitting displays, diamond technologies, and advanced nano‐coatings. Since its inception, COSDAF has trained over 450 PhD students and postdoc fellows, many of them now serve as faculty members and leading researchers in various universities, research institutes, and industries worldwide. Additionally, COSDAF has cultivated strong collaboration with high‐tech local industries, providing training and resources for research staff and students. This has established an important platform that bridges the gap between academia and industry.