The aim of this case study is to demonstrate how a co-design approach could be used within design-based research (DBR) with diverse multi-stakeholders in the LUMA1 ecosystem to promote social creativity towards novel student-based solutions and pedagogical innovations. As a case, a national LUMA2020 development program (2019-2020), organized by the national LUMA Centre Finland and funded by the Finnish Ministry of Education and Culture, was studied in detail. The different data sources (e.g. an action plan, written observations) were analysed through qualitative content analysis. The Edelson's design-based research model used in the program offered a systematic framework or a map for codesigning both the action plan and its implementation. The co-design approach within the model was organised through three stages to engage all multistakeholders (altogether about three hundred participants) for it: (i) a research and societally oriented framework stage, (ii) a practical stage and (iii) a "bottom-up" stage in which teachers from 160 schools were active participants and professional key contributors. The co-design approach and the design decisions were facilitated by using guided face-to-face communication in small group work and digital creative learning spaces as a medium for social creative thinking. The co-designers were teachers, teacher educators, scientists or industry specialists in different stages. The co-design model used could be a way to bridge the newest research and innovations into praxis for supporting the curriculum at the school level and for promoting teachers' professional development by forming creative and diverse learning communities, in which all partners can learn from each other through sharing.