A novel solvothermal method has been successfully developed to prepare nanocrystalline CuSbS 2 and Ag 3 SbS 3 by the reactions between CuI and AgNO 3 with SbCl 3 and elemental sulfur in ethylenediamine at 140 o C for 12 h, respectively. XRD, TEM and XPS examinations investigated the phase, grain size, morphology and purity of the products, respectively. Ethylenediamine played important roles in the formation of the ternary sulfides. A possible mechanism is proposed and expected to explain similar reactions.