The synthesis of the perbrominated arsaboranes closo‐1,2‐As2B4Br4 (1) and closo‐1,2‐As2B10Br10 (2) occurs by co‐pyrolysis of B2Br4 and AsBr3 at 500 °C. Repeated fractionation of the sublimable products in vacuo yields both compounds in pure form. The X‐ray structure determination for orthorhombic closo‐1,2‐As2B4Br4 (1) [space group: Pbcn, a = 2345.48(17) pm, b = 627.31(4) pm, c = 1294.02(9) pm for Z = 8] and the corresponding phosphorus compound, monoclinic closo‐1,2‐P2B4Br4 (3) [space group: P21/n, a = 806.84(6) pm, b = 1247.96(9) pm, c = 974.91(7) pm, β = 90.493(3)° and Z = 4] confirmed that both 1 and 3, consistent with their 14‐skeletal electron counts, adopt octahedral structures distorted from regular by two arsenic or phosphorus atoms in the 1,2‐positions. The shortest boron–boron bonds within the cluster frameworks are located between the boron atoms antipodal to the heteroatoms.