Reaction kinetics of p-benzoquinone- p-dihydroxybenzene; p-benzoquinone- m-dihydroxybenzene and p-benzoquinone- o-dihydroxybenzene systems have been studied in the solid state using capillary, gravimetric, and dilatometric techniques. It is found that p-benzoquinone is the diffusing species. The diffusion occurs through surface migration and depends very much on the symmetry of the dihydroxybenzene molecules. Gravimetric studies indicate that cracks are formed in the product during reaction and that the reaction reaches completion. Dilatometric studies indicate that the reaction products are more compact and contraction in volume takes place during the course of reaction.