The two new quaternary thioantimonates(III) BaAgSbS3 (1) and BaAgSbS3 center dot H2O (2) have been synthesized through a hydrazine-hydrothermal method at low temperature. Compound 1 possesses a two-dimensional (2D) layer structure, while compound 2 features a three-dimensional (3D) channel framework. The optical band gaps of 1 and 2 are approximately 2.2 and 2.4 eV, respectively. Our results clearly indicated that the hydrazine-hydrothermal method could offer exciting opportunities for exploring novel multinary chalcogenides with diverse crystal structures and interesting physical properties.