The reaction of Ir with Se and SeBr₄ at 200 °C yields shiny vermillion slate-like crystals of the new compound Ir₄Se₁₀Br₁₆. Single-crystal X-ray diffraction revealed an orthorhombic unit cell, space group Pccn, with lattice parameters a = 1515.0(1) pm, b = 1534.4(1) pm, and c = 1514.5(1) pm at 296(1) K. The crystal structure consists of uncharged tetranuclear iridium complexes [Ir₄Se₁₀Br₁₆] with C₂ symmetry. In the [(Ir³⁺)₄(μ₄-η²-Se₂^2-)₂(μ-η^Se-[SeBr]^-)₂(η^Se-SeBr₂)₄(μ-Br^-)₂(Br^-)₄] complex, each of the iridium atoms is coordinated octahedrally by four selenium and two bromine atoms. Selenium adopts three different oxidation states: -I in the fourfold-bonded diselenide dumbbell, ±0 in the bridging [SeBr]^- unit, and +II in the terminal SeBr₂ ligand. An analogous reaction with SeCl₄ at 300 °C yields orange air-stable crystals of Ir₆Se₈Cl₃₀. The triclinic crystal structure [space group P\bar {1}, a = 891.2(1) pm, b = 1064.6(1) pm, c = 1263.0(1) pm, α = 94.458(3)°, β = 106.900(3)°, and γ = 101.410(3)° at 296(1) K] consists of uncharged hexanuclear iridium complexes with the structured formula [(Ir³⁺)₆(μ-η^Se-[SeCl]^-)₂(η^Se-SeCl₂)₆(μ-Cl^-)₁₀(Cl^-)₆] and shows structural motifs similar to Ir₄Se₁₀Br₁₆ and IrSeCl₅. The triclinic structure of IrSeCl₅ [P\bar {1}, a = 1223.4(1) pm, b = 1408.7(1) pm, c = 1499.5(1) pm, α = 115.72(1)°, β = 106.05(1)°, and γ = 96.38(1)° at 296(1) K] is homeotypic to monoclinic RhSCl₅.