The ternary thallium chalcogenides of the general formula Tl(4)MQ(4) (M = Zr or Hf; Q = S or Se) were obtained from high-temperature reactions without air. These sulfides and selenides are isostructural, crystallizing in the triclinic system with space group P (1) over bar and Z=5, in contrast to Tl4MTe4 compounds that adopt space group R (3) over bar. The unit cell parameters for Tl4ZrS4 are as follows: a = 9.0379(5) angstrom, b = 9.0375(5) angstrom, c = 15.4946(9) angstrom, alpha = 103.871(1)degrees, beta = 105.028(1)degrees, gamma = 90.138(1)degrees, and V = 1183.7(1) angstrom(3). In contrast to the corresponding tellurides, the sulfides and selenides exhibit edge-shared MQ(6) octahedra, propagating along the c axis in a zigzag manner. All elements occur in the most common oxidation states, according to the formulation (Tl+)(4)M4+(Q(2-))(4). Electronic structure calculations predict energy band gaps of 1.7 eV for Tl4ZrS4 and 1.3 eV for Tl4ZrSe4, which are in accordance with the large resistivity values observed experimentally.