The synthesis, crystal structure, nonlinear optical (NLO) property and some other properties of a new material, Hg(2)BrI(3), are reported. The crystal structure has been established by single crystal X-ray diffraction studies. Hg(2)BrI(3) belongs to the HgBrI type and crystallizes in the orthorhombic space group Cmc21 (No. 36). The compound shows a phase-matchable second harmonic generation (SHG) of about 1.2 times as strong as that of KTiOPO(4) (KTP) based on the powder SHG measurement. It exhibits a wide transparency in the IR region (from 2.5 to 30 μm), and a good thermal stability. It is believed that Hg(2)BrI(3) is a new candidate for NLO materials in the IR region.