<p>Lanthanide doped non-metal molecular clusters are a research hotspot due to their potential applications in materials such as semiconductors, catalysis, and detector. To explore the structure and properties of La doped S molecular clusters, the neutral and anionic La₆S_<i>n</i>^0/− clusters (<i>n</i> = 1–12) were investigated by using the density functional theory (DFT) method. The structural evolution law of neutral ground state molecular clusters La₆S_<i>n</i> (<i>n</i> = 1–12): When <i>n</i> = 1–8, the increased S atoms are sequentially adsorbed on the surface of La₆ octahedron. When <i>n</i> = 9–12, one S atom is adsorbed inside the La₆ octahedron, while the other S atoms are adsorbed on the different surface of La₆ octahedron. The structural evolution law of anionic molecular clusters La₆S_<i>n</i>^<i>−</i> (<i>n</i> = 1–12) is basically consistent with neutral ones, except that the structure of <i>n</i> = 9–12 is slightly different. The stability calculation of the ground state structure indicates that the La₆S₈⁻ molecular cluster shows strong thermodynamic and relative stability. The adaptive natural density partitioning (AdNDP) and density of states (DOS) exploration of the La₆S₈⁻ molecular cluster confirmed that the interaction between La and S atoms enhances the stability. Furthermore, the simulated the ultraviolet-visible (UV-vis) spectra suggests that La₆S₈⁻ is candidate material for efficient solar cells and high-performance photodetection devices.</p>