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.