The California NanoSystems Institute (CNSI) was State-chartered to advance the development of nanotechnology through partnership between university faculty members and students with California and national industry laboratory scientists. As a new science requiring a multidisciplinary approach to develop informational, biomedical, and manufacturing technologies, nanotechnology presents a unique set of programmatic challenges both to the research scientists and to those designing their research spaces. Lab plans must be flexible enough to accommodate the constant evolution of research methods that characterize development in this field.Commissioned by CNSI, Rafael Viñoly Architects was challenged to accommodate a large building that required maximum flexibility on a steep slope in a densely developed area between the Court of Science and an existing garage. RVA’s proposal for a long span steel structure to take advantage of the space above the garage allows the building to be developed horizontally instead of vertically, thereby facilitating greater interaction among the users.More than fifty percent of the seven-story building consists of lab space. The remainder comprises offices, conference/meeting rooms, exhibition spaces, a data center, and a 260-seat auditorium. Light, vibration, and electromagnetic-sensitive functions such as engineering, low-noise physics, electron microscopy labs, and Class 1000 and 100 clean rooms for semiconductor fabrication, are located in the lowest two levels where cast-in-place concrete structure built into the earth slope offers best protection. One level, dedicated to animal imaging, is built around state-of-the-art small-animal imaging technology and its support requirements, which include animal housing, procedure rooms, data analysis, and a cyclotron facility for production of radiopharmaceuticals.Labs for making, measuring, and modeling nanosystems, as well as transferring them for the global marketplace, are located on the upper three levels, partly spanning the garage. A mid-air courtyard with walkways, stairs, bridges, and roof terraces, provides researchers with lively outdoor circulation and public spaces that offer frequent opportunities for casual meetings and exchange.