Na7RbTl4 has been prepared by solid state reaction from the elements. Single crystal X-ray structure analysis suggested the presence of pseudo-merohedral twinning. The final model could be derived in space group Pbam (a=16.3584(4) angstrom, b=16.3581(4) angstrom, c=11.3345(3) angstrom, V=3033.04(14) angstrom(3), R-1/wR(2) 0.0282/0.0402) and proved the presence of isolated [Tl-4](8-) anions, which are only known from two other solid state thallide phases so far. The structure of Na7RbTl4 is compared to the long-known Na2Tl and the similarities and differences in the three-dimensional arrangement within the crystal structures are reported on. DOS calculations revealed a pseudo-band gap at E-F. Dissolution experiments in the style of the chemistry of group 14 and group 15 Zintl anions in liquid ammonia yielded degradation of the thallides. Subsequent characterization of the reaction products by powder X-ray diffraction allowed for the determination of alkali metal amide and elemental thallium as products.