for MoS 2x Se 2−2x , [5][6][7][8][9][10] WS 2x Se 2−x2 , [11,12] and ReS 2x Se 2−2x . [13,14] In addition, alloying transition metal atoms in ternary Mo x W 1−x S 2 [15][16][17] and Mo x W 1−x Se 2 [18,19] has enabled engineering of dark and bright excitonic states, exciton binding energies, and quasi-and single-particle band gaps to create highly luminescence 2D semiconducting materials. In these material systems, 2D alloying is commonly accomplished across the same crystalline phases, that is, across 2H-MoS 2 to 2H-MoSe 2 or 2H-WSe 2 to 2H-MoSe 2 by alloying Se into MoS 2 or Mo into WSe 2 , respectively. Overall, these well-investigated alloy systems retain their crystalline structure and phases independently from the composition values.Unlike graphene, however, 2D inorganic mono-, di-, and tri-chalcogenides can crystallize in different phases while keeping their 2D nature. For instance, MoTe 2 is stable in both hexa gonal (2H) and monoclinic (1T') phases whereas WTe 2 crystallize only in 1T' phase in nature. [20,21] Large changes in the crystal structure naturally affect their electronic band structures and as a result, these two phases exhibit semiconducting and metallic behavior in 2H and 1T' phases, respectively, and the structural (2H) and electronic (semiconducting) phase of MoTe 2 can be effectively engineered by laser irradiation [22] or W substitution. [23][24][25] Recently, it has been experimentally demonstrated that these two phases can be controlled on demand through electrolyte gating [26] which introduces a large density of carriers into the 2D sheets and in return increases the total energy of 2H-MoTe 2 to the values of 1T'-MoTe 2 to induce structural transformation. This effect heavily relies on identification of 2D material systems that exhibit formation (total) energies close enough to each other so that one phase can be destabilized over another to induce desired phase changes. However, the library of 2D materials offers only a few candidates with the aforementioned close formation energies, and there is a search for new material systems that can potentially offer easier phase changes (closer formation energies) and broader functionality (band gap range, metal-insulator versus semiconductor-insulator).In this work, we demonstrate for the first time, the novel alloying effects across two different phases pseudo-1D Alloying selected layered transitional metal trichalcogenides (TMTCs) with unique chain-like structures offers the opportunities for structural, optical, and electrical engineering thus expands the regime of this class of pseudoone-dimensional materials. Here, the novel phase transition in anisotropic Nb (1−x) Ti x S 3 alloys is demonstrated for the first time. Results show that Nb (1−x) Ti x S 3 can be fully alloyed across the entire composition range from triclinic-phase NbS 3 to monoclinic-phase TiS 3 . Surprisingly, incorporation of a small concentration of Ti (x ≈ 0.05-0.18) into NbS 3 host matrix is sufficient to induce triclinic to monoclinic transition. Theoretical studies s...