2,3-Dihydro-2,2,2-triphenylphenanthro[9,10-d]-1,3,2-λ⁵-oxazaphospholes react with carbon dioxide in an overall second order reaction at room temperature to give 3H-phenanthro[9,10-d]oxazol-2-ones and triphenylphosphine oxide in good yields. Nucleophilic attack of the phenolate on CO₂ and formation of Ph₃PO was found.