Fluorescence Yield Near Edge Spectroscopy (FYNES) of ultra low Z materials represents a synchrotron radiation milestone for in-situ determination of local structure for a range of materials problems from monolayers to bulk samples even in the presence of a reactive atmosphere. Two examples will be presented highlighting the broad range of materials problems addressed by the FYNES technique. First a study of the kinetics of CO displacement on Ni(100) by hydrogen at pressures up to.1 torr. These kinetic results highlight the unique capabilities of FYNES to directly characterize surface reaction rates in the presence of reactive gases. Second, a pioneering fluorescence EXAFS study characterizing low concentration fluorine materials will be discussed. Finally new opportunities in FYNES presented by increased photon flux from insertion-device- based sources will be explored.