A new 0D iron-based magnetic chalcohalide, Ba3FeS4Br, has been prepared by the spontaneous crystallization method. It crystallizes in the orthorhombic space group Pnma. Interestingly, the structure contains a Ba–Br reticulate structure in which isolated FeS4 tetrahedra are located. Its band gap was experimentally determined to be 1.65 eV. Despite the large separation between the Fe atoms, with the shortest distance being more than 6.33(2) A, temperature-dependent magnetic susceptibility and field-dependent magnetization measurements on Ba3FeS4Br unexpectedly showed an antiferromagnetic phase transition at 85 K, which may be due to the antiferromagnetic super exchange of Fe3+ spins.