Black, air-insensitive crystals of the bismuth-rich tetra-iodido- indate(III) (Bi₈)₃Bi[InI₄]₉ have been prepared from melts of the contributing elements. X-ray diffraction on a single crystal at 293 K and 220 K revealed a cubic structure with [InL ₄]^- tetrahedra, isolated Bi³⁺ ions and rotationally disordered Bi₈²⁺ square anti-prisms ace group Fm3̄c; a = 20.162(2) Å at T = 293(1)]. The principal arrangement of the complex ions corresponds to the AuCu₃ type. The small bulk modulus B_o = 12(1) GPa and its large pressure derivative B _o' = 11(1) as well as the low Debye temperature θ_D = 52 K are in accordance with a plastic behavior. Cooling below 148(1) K induces the first order transition into an ordered phase with 0.43 % higher density but much larger unit cell and lower crystallographic point group. The transition enthalpy AH ≈ 3.8 kJ-mol^-1 and transition entropy AS ≈ 3 R were determined from specific heat data. A similar reversible phase transition into a lower symmetric structure is observed at a pressure of approximately 5 GPa. (Bi₈)₃Bi[InI₄]₉ is a diamagnetic semiconductor.