This tutorial review focuses on the recent advances in the topic of mixed inorganic materials, specifically rare-earth mixed inorganic materials, which have similar crystal structures to the parent material. In this review we overview the available synthetic methods employed to prepare rare-earth mixed inorganic materials and the common approaches to characterize the differences in the crystal structures when the composition varies within the mixed material. The luminescence properties are investigated after adjusting the composition of the mixed material and doping with suitable lanthanides. We focus on understanding their luminescence performance, which is a crucial step for designing new materials, and exploring their future applications. Last, the possible applications of such rare-earth mixed inorganic materials are also described and further prospects of the exploration of such materials are presented.