  In the last decade the ns$^2$ cations (e.g., Pb$^{2+}$ and Sn$^{2+}$) based
halides have emerged as one of the most exciting new classes of optoelectronic
materials, as exemplified by for instance hybrid perovskite solar absorbers.
These materials not only exhibit unprecedented performance in some cases, but
they also appear to break new ground with their unexpected properties, such as
extreme tolerance to defects. However, because of the relatively recent
emergence of this class of materials, there remain many yet to be fully
explored compounds. Here we assess a series of bismuth/antimony oxyhalides and
chalcohalides using consistent first principles methods to ascertain their
properties and obtain trends. Based on these calculations, we identify a subset
consisting of three types of compounds that may be promising as solar
absorbers, transparent conductors, and radiation detectors. Their electronic
structure, connection to the crystal geometry, and impact on band-edge
dispersion and carrier effective mass are discussed.
