The article discusses the valley-selective circular dichroism (VSCD) in monolayer molybdenum disulfide (MoS2), a two-dimensional material with a honeycomb lattice structure. The key challenge in valleytronics is achieving valley polarization, which can be achieved through VSCD. The authors use first-principles calculations to show that MoS2 is an ideal material for valleytronics due to its unique symmetry, which allows for valley polarization. Experimental evidence is provided through circularly polarized photoluminescence measurements, which show up to 50% polarization. The study also explores the microscopic origin of chiral optical selection rules and the role of Berry curvature in electronic transport properties. The findings suggest that MoS2 could be a promising material for valleytronics, with potential applications in optoelectronic devices and next-generation electronics.The article discusses the valley-selective circular dichroism (VSCD) in monolayer molybdenum disulfide (MoS2), a two-dimensional material with a honeycomb lattice structure. The key challenge in valleytronics is achieving valley polarization, which can be achieved through VSCD. The authors use first-principles calculations to show that MoS2 is an ideal material for valleytronics due to its unique symmetry, which allows for valley polarization. Experimental evidence is provided through circularly polarized photoluminescence measurements, which show up to 50% polarization. The study also explores the microscopic origin of chiral optical selection rules and the role of Berry curvature in electronic transport properties. The findings suggest that MoS2 could be a promising material for valleytronics, with potential applications in optoelectronic devices and next-generation electronics.