In2ThBr6, a reduced indium bromide containing univalent indium and tetravalent thorium, is synthesized from indium tribromide, thorium tetrabromide, and elemental indium at moderate temperatures. The monoclinic crystal structure, determined via Rietveld refinement of high-precision X-ray powder diffractometerer data (a = 879.12(1) pm, b = 1467.00(2) pm, c = 904.64(1) pm, beta = 91.153(1)degrees; C2/c; Z = 4), is built up from three-dimensionally interconnected ThBr84- bisdisphenoids and InBr98- monocapped cubes, the latter polyhedra being significantly distorted. The analysis of the chemical bonding of In2ThBr6, as well as the explanation of the novel compound’s weak paramagnetic susceptibility (direct van Vleck type), is based on abinitio all-electron scalar-relativistic band structure calculations.