Knowledge cities may be understood as cities that rely primarily on the global knowledge economy such that they attract the creative class in our globalized world. Examples include but are not limited to New York City and San Francisco. As East Asia undergoes rapid urbanisation, more cities, e.g., Shenzhen, are modelled to capture the economic benefits of ‘knowledge spillovers’ (Henderson, 2007). The Knowledge Spillover Theory suggests that innovation is concentrated in some quarters of the city because of informal social exchanges across co-located industries. Business incubators are often introduced to accelerate these processes. For instance, Launchpad@One-north, Singapore, is surrounded by media corporations, a university, a business park, mass transit, and nature areas. The Greater One-north area required spatial planning as more intensive developments were expected to serve future housing along the southern waterfront. Action research-by-design was employed to examine the economy-ecology outcomes from scenarios of varying densities. In this paper, we identify two types of economy-ecology synergies that may be achieved by careful spatial design for socio-ecological encounters. Four scenarios with different orientations toward the economy-ecology dichotomy illustrate these to varying degree. Overall, a high-quality environment is synergistic. Simultaneously centring humans and nature may attract talent and accelerate innovation in knowledge cities.