In the present study, we have analyzed the seed yield and seed quality of pigeonpea grown under elevated CO₂. Pigeonpea was grown for its complete life cycle in open top chambers under elevated CO₂ (600 µmol/mol) and atmospheric ambient CO₂ (400 µmol/mol). The growth, biomass and seed yield were increased under elevated CO₂ when compared to plants grown at ambient CO₂ concentrations. The mature seeds were collected after 120 days for various biochemical analyses to determine their nutritional quality. The biochemical analyses indicated that elevated CO₂ grown pigeonpea seeds did not show any significant decrease in nitrogen and protein contents but showed an increase in total carbohydrates. The metabolomics of seeds revealed changes in sugars, amino acids, organic acids and fatty acid levels under elevated CO₂ growth. The seeds collected from elevated CO₂ grown pigeonpea showed higher levels of essential amino acids inferring their better nutritional quality. The total proteome of pigeonpea seed was studied through label-free quantification and recorded an increase in several seed specific proteins including certain stress related proteins in elevated CO₂ grown pigeonpea seeds. The proteome and metabolome data demonstrate better seed vigor in elevated CO₂ grown pigeonpea.