This session will delve into the co-evolution of spatial and institutional dynamics in urban development, highlighting how design entrepreneurship acts as a catalyst for urban transition. We choose the Luchtsingel project in Rotterdam, initially launched as temporary urban infrastructure that revitalized local development before becoming permanent, as our case study. This city-making initiative combined public (crowdfunding and community-building practices), bureaucratic (the City Initiative), and professional (the 5th IABR) forces, providing a rich context to identify the actors and their strategic actions throughout the transition process. By dissecting these interactions, we aim to uncover the mechanisms that drive changes in urban landscapes and influence policy-making. The session will offer researchers, professionals, officials, the public, and communities insights into how emergent design decisions can lead urban transitions by interacting with socio-cultural and spatial-political conditions. Our goal is to encourage the transformative potential to nurture more urban experiments for sustainable development. We aim to provide both theoretical frameworks and actionable insights at PWE ‘24, to understand and drive urban change through design experiments.