Single crystals of two new chalcogenides CsSc 5 Te 8 and Cs 0.6(1) Ti 6 Se 8 were synthesized by the high-temperature solid-state sealed tube method using a reactive flux (CsCl) at 1223 K. The crystal structures of CsSc 5 Te 8 and Cs 0.6(1) Ti 6 Se 8 were determined by single-crystal X-ray diffraction method. The compound CsSc 5 Te 8 crystallizes in the monoclinic space group C 2 h 3 −C 2/ m with the lattice parameters a = 21.3376(15) Å, b = 4.1434(3) Å, c = 10.2853(7) Å, and β = 103.925(2)° having the two formula units (Z = 2). The asymmetric unit of CsSc 5 Te 8 contains eight crystallographically independent atomic sites: Cs1 (site symmetry: 2/ m), Sc1 (m), Sc2 (m), Sc3 (2/ m), Te1 (m), Te2 (m), Te3 (m), and Te4 (m). The structure of CsSc 5 Te 8 is built up of the three-dimensional anionic framework of 3 ∞ [ Sc 5 Te 8 ] 1 − where the Sc atoms are octahedrally coordinated with six Te atoms forming the one-dimensional tunnels approximately along the b -axis where the Cs+ cations are present. The compound Cs 0.6(1) Ti 6 Se 8 crystallizes in the Nb 3 Te 4 structure type with Z = 1, in the hexagonal space group C 6 h 2 −P 6 3 / m having cell dimensions of a = b = 9.9520(1) Å and c = 3.5710(1) Å. The asymmetric unit of Cs 0.6(1) Ti 6 Se 8 structure is composed of four crystallographically independent sites with atoms Cs1 (site symmetry: 6 ‾..), Ti1 (m..), Se1 (m..), and Se2 (6 ‾..). The Ti atoms are making distorted octahedral units by coordinating with six Se atoms. These TiSe 6 distorted octahedra share edges and corners with the adjacent TiSe 6 units to form three-dimensional anionic networks that generate one-dimensional tunnels approximately along the c -direction. The optical absorption measurements show that CsSc 5 Te 8 is a semiconductor having a direct bandgap of 1.2(1) eV at room temperature consistent with the DFT studies. [Display omitted] • Single crystals of CsSc 5 Te 8 and Cs 0.6(1) Ti 6 Se 8 were obtained using the molten flux method. • CsSc 5 Te 8 is made up of the three-dimensional anionic framework of 3 ∞ [ Sc 5 Te 8 ] 1 − . • Cs 0.6(1) Ti 6 Se 8 can be described as a three-dimensional framework of 3 ∞ [ [ Ti 6 Se 8 ] 0.6 − . • CsSc 5 Te 8 shows a direct bandgap of 1.2(1) eV. • Electronic structure calculations for CsSc 5 Te 8 indicate a bandgap of 1.27 eV. [ABSTRACT FROM AUTHOR]