The present review describes a ruthenium-catalyzed ortho C-O bond formation such as hydroxylation, benzoxylation and acetoxylation of substituted aromatics with oxygen nucleophiles via C-H bond activation. Various oxygen sources such as trifluoroacetic anhydride, aromatic carboxylic acids and acetic acid are used as nucleophiles in the reaction. Most of the reactions shown in the review mechanistically proceeds via a concerted deprotonation ortho metalation pathway. A five- membered ruthenacycle intermediate was proposed in the reactions. These reactions provide an efficient route for the synthesis of orr/io-hydroxy-, acetoxy- And benzoxy substituted aromatics in a highly regioselective manner in one pot.