Technological innovation in general, and nanotechnology development in particular, happens often disconnected from people and places where these technologies eventually play out. Over the last decade, a diversity of approaches have been proposed and developed to engage people in the innovation process of nanotechnology much earlier than in their conventional role as consumers. Such “upstream” engagements are conducted at stages when nanotechnology products and services are still amenable to reframing and modification. These engagement efforts have enhanced technological literacy among stakeholders (...) and the general public. Yet, there is still potential for other types of impacts by leveraging links between nanotechnology and people’s everyday experiences. The present study explores a novel approach for participatory nanotechnology assessment and design, called Collaborative On-site Technology Exploration. The approach allows nanoscale scientists and engineers to explore nanotechnologies where they matter to people and places. We conducted a series of COTEs in the Gateway district in Phoenix addressing community challenges of renewable energy supply, water contamination, and public health issues. COTEs are proposed as a step toward bringing together nanoscale scientists and engineers and community stakeholders in need for solutions to urban challenges. (shrink)