Two successful sample return missions to C-type asteroids have shaped recent research activities on asteroidal materials around the globe. As members of JAXA's Hayabusa2 mission initial analyses team and NASA's ongoing OSIRIS-REx mineralogy and petrology working group (MAPWG) for the initial analyses, we plan to benefit from the unprecedented availability of unique pristine sample sets of two similar asteroids which experienced very different geological histories. In our project we will focus on the formation conditions and evolution of carbonates and phosphates in these materials as these are the main carriers of volatiles like C, F, Cl and OH and REEs and therefore best represent the complex hydrous evolution of these fluid and organic rich asteroids. The application of our non-invasive 2D/3D confocal and tomographic synchrotron radiation X-ray fluorescence (SR-XRF) methods at selected synchrotron beamlines, complemented by state-of-the art transmission electron microscopy (TEM), combining high spatial resolution and low detection limits, will ensure the most complete and accurate compositional investigation possible regarding major, minor and trace elements within the Bennu rocks and the most reliable scientific findings.