Two kinds of chalcogenides with layered composite crystal structures have been formed in Bi-Ta-S and Bi-Ta-Se systems depending on the preparation conditions : (BiS)(1.08)TaS2 and (BiS)(1.08)(TaS2)(2) for the former system and (BiSe)(1.09)TaSe2 and a new selenide (BiSe)(1.09)(TaSe2)(2) for the latter. The new chalcogenide has been characterized by powder X-ray diffraction and electron diffraction. The atomic coordinates in the layer-stacking direction of the new chalcogenide and its hydrazine intercalation compound have been determined. The electrical resistivity measurement has suggested that all of these chalcogenides are low temperature superconductors.