Mn²⁺ doped garnet-type Na₂CaSn₂Ge₃O₁₂ phosphor was selected and studied due to its abundant chemical compositions and several crystallographic sites. Several ion substitution strategies including the chemical substitution of Na⁺/Sr²⁺/Ba²⁺ on Ca²⁺ sites and the anti-site occupation of Sn⁴⁺/Ge⁴⁺ were designed for regulating the different energy traps and promoting multimode luminescence properties like persistent luminescence, X-ray storage capacities and mechano-luminescence. In addition, the X-ray luminescence storage and mechano-luminescence properties of these materials as well as their applications on X-ray luminescence extension imaging and stress sensing were also investigated.