NIST works with Florida State University to make single-molecule magnets less than five nanometers (nm) in diameter, and works with the University of Colorado at Boulder to make nanocrystals in the 10-50 nm range. The agency is pioneering methods for manipulating and measuring the magnetic properties of these compounds and is developing instrumentation for understanding how contrast agents work and how to control contrast properties. Researchers correlate the measured properties to the observed MRI response under non-clinical conditions using imagers at The Children's Hospital in Denver. The information gained is fed back into recipes for making even better nanomagnets. The work described in the new paper was supported in part by the National Science Foundation.