Spectroscopic evidence is presented that shows that boron nitride andaluminum oxide can be synthesized by exposing a condensed layer of molecular precursors to synchrotron radiation. In the A12 O3 circumstance a condensed layer of trimethylaluminum (TMA)and water at 78 K on a silver substrate produces pure layers of aluminum oxide. Using the same condensed layer technique boron nitride is produced by exposing a solid matrix of diborane and ammonia to synchrotron radiation. Near edge x-ray absorption fine structure and core level photoelectron spectroscopies are used to characterize the A12 O3 and BN layers, which were typically 30Å thick. During the formation of aluminum oxide the carbon component inthe alkylaluminum precursor is completely removed during irradiation as a volatile methane product which was detected by mass spectrometry. In the absence of synchrotron radiation the molecular precursors in both the aluminum oxide and boron nitride systems show evidence of some interactions within the solid, but upon warming to near room temperature (260 K) the layers desorb from the substrate.