Chalcogels are three-dimensional porous networks with unique applications in catalysis, gas adsorption, energy storage, and environmental remediation. Here, we demonstrate the efficacy of antimony sulfide chalcogels for the selective sequestration of organic dyes from aqueous solutions. The chalcogels exhibit high adsorption capacities for the dyes rhodamine B (RhB), methylene blue (MB), and methyl violet (MV), however, display poor adsorption capacity for the orange G (OG) dye. Lewis-basicity of chalcogel's network is responsible for selective affinity toward RhB, MB, and MV, thus favoring the capture of electron accepting dyes through Lewis acid-base interactions. The adsorption kinetics obeys the pseudo second-order model rather than the pseudo first-order model, and the equilibrium adsorption data fits well to the Langmuir isotherm equation. Dye removal efficiencies up to 99% are achieved in 30 min for an initial concentration of 25 mg/100 mL of the aqueous dye solutions. Langmuir adsorption capacities are found to be 442, 303, and 210 mg/g for RhB, MB, and MV, respectively. Using the selective adsorption behavior of antimony sulfide chalcogels, separation of mixed dyes MB/OG (RhB/OG) is realized through molecular filtration. These results suggest that chalcogels are potential candidates for the treatment of industrial effluents, thus providing a new platform for molecular filtration of organic dyes and other organic molecules.