Department of Chemistry. Jadavpur University, Kolkata-700 032, India E-mail : mallikak52@yahoo. co. in Manuscript received OJ June 2012, accepted 11 July 2012 Efficient and rapid solvent-free methods have been developed for synthesis of 1 ,8-dioxo-octahydroxanthenes by microwave irradiation of cyclohexane-1,3-diones with aromatic aldehydes in presence of either amberlyst-15 or benzoic acid as catalyst. 2,2'-(Phenylmethylene)bis(3-hydroxy-5,5-dimethylcyclohex-2-en-1-ones) could be obtained from the same starting materials by microwave irradiation either over neutral alumina or directly. All these methods are ceo-friendly.