We propose to search for the infrared absorption features due to nitrogen-containing UV photoproducts and to sulfur containing molecules in interstellar ices. In addition, the proposed spectral region encompasses absorption features due to the C-H bending modes of organic species (e.g., methanol). Detection of the nitrogen photoproducts would greatly enhance our understanding of the UV photoprocessing of interstellar ices, and could, by inference of the parent molecules, also yield significant information on the potentially important ice mantle species N2 and NH3, for which the abundances in the ices are currently not well known. Similarly, detection of sulfur containing species in interstellar ices would greatly enhance our knowledge of the sulfur chemistry in dense clouds, which currently suffers from a lack of information on the chemical state of sulfur in this environment. Thus, these observations could make an important contribution to understanding the chemical processes in dense clouds. The proposed observations supplement the central program, filling up some important gaps with respect to wavelength coverage and object variety.