High-quality crystals of BaGa 4 Se 7 , a newly developed IR nonlinear optical (NLO) material, were obtained via the Bridgman–Stockbarger technique. The FWHM of the (002) peak rocking curve is about 0.008° and the transmittance through a polished 2mm thick (001) plate is around 65% over the wide range of 1–14μm. Various thermophysical properties were measured on crystals. The thermal expansion behavior in BaGa 4 Se 7 does not exhibit strong anisotropy with α a =9.24×10 −6 K −1 , α b =10.76×10 −6 K −1 , and α c =11.70×10 −6 K −1 along the three crystallographic axes. The thermal diffusivity/thermal conductivity coefficients measured at 298K are 0.50(2)mm 2 s −1 /0.74(3)Wm −1 K −1 , 0.42(3)mm 2 s −1 /0.64(4)Wm −1 K −1 , 0.38(2)mm 2 s −1 /0.56(4)Wm −1 K −1 , along the a, b, c crystallographic axis respectively. In addition, the surface laser damage threshold was measured to be 557MW/cm 2 using a Nd:YAG (1.064μm) laser under conditions of 5ns pulse width, 1Hz frequency, and D=0.4mm spot size.