© 2015 Optical Society of America. We report on crystal-field engineering of solid-state laser gain media based on new transition metal (TM) (iron) doped II-VI ternary and quaternary semiconductor materials for middle-infrared (mid-IR) tunable laser applications. Novel ternary and quaternary TM:II-VI materials were fabricated in powder form using thermal annealing of mixtures of commercially available binary powders sealed in evacuated quartz ampoules. These resultant powders were characterized using XRD, micro- Raman spectroscopy, photoluminescence (PL) and PL kinetics. We demonstrate: 1) that this synthesis method enables laser active powder media and is an effective means to fabricate and prototype novel laser active materials, 2) by introducing heavier or lighter ions into the host crystal lattice, it is possible to independently engineer the spectral positions of the absorption and PL band of TM ions in II-VI crystals, and 3) the first time to our knowledge room temperature, mirrorless, random lasing of iron doped Zn0.5Cd0.5Te powders at 5.9 μm.