Abstract. Knowledge-based urban developments (KBUDs) are an increasingly common element of urban planning and strategy making: policy makers and developers set out to stimulate economic prosperity by promoting the integration and concentration of research, technology, and human capital. But KBUD is, by its advocates' own admission, a fuzzy concept, assuming that local physical development will drive urban upgrading within wider innovative production networks. We seek to address one element of this confusion by exploring how physical developments actively create innovative connections between local actors, drawing on the microscale science park and incubator literature. Using the case of one knowledge precinct, Kennispark in the east of the Netherlands, we investigate how active and passive elements of KBUDs drive integration of knowledge infrastructure in the urban fabric, as a prerequisite to building cross-city connections. On the basis of both qualitative and quantitative data, we conclude that there is a dynamic interrelation of proximity and connectivity within the precinct that contributes to building within-city knowledge communities that may in turn lead to improved cross-city connectivity and hence urban upgrading.