When modern spectral hole burning applications for high-density information storage under noncryogenic temperatures are envisioned, it is necessary to develop new frequency-selective photoactive materials for this purpose. Mixed compounds of the PbFCl family, doped with samarium(II) ions, exhibit promising and true room-temperature hole burning capabilities. We investigate this class of systems (and related ones) by combining material synthesis and high-resolution spectroscopy. Whole groups of isomorphous crystals were synthesized with varying degrees of halide anion and/or cation substitutions. Thin films of fluoride-based materials were made in a laboratory-built molecular beam epitaxy system. An extended x-ray study, differential thermal analysis, luminescence, and Raman measurements allowed the characterization of the materials. Formal models were developed for both the inhomogeneous zero-phonon optical line shapes of the samarium(II) and the time evolution of the hole burning.