The cover picture shows isolated [Tr4]8– tetrahedra present in the unit cell of the new ternary trielides Na7KTr4 (Tr=In, Tl). The firework of alkali metals and the trielides represent the synthetic route by high temperature solid state reaction, which was used for the syntheses of the title compounds. Na7KTr4 (Tr=In, Tl) were characterized by single crystal X‐ray structure analyses as well as 23Na solid state NMR spectroscopy. Theoretical calculations reveal insight in the electronic nature of these compounds. Dissolution experiments of the alkali metal indides in liquid ammonia showed an oxidation of the [In4]8– tetrahedra under the formation of a three‐dimensional indium network in NaIn, which can be interpreted as first evidence for a reactivity of trielides according to the well‐established chemistry of salt‐like tetrelides in this solvent. (DOI: 10.1002/zaac.202300112).