NOVELTY - Synthesis of alpha , alpha '-dibenzylidenecyclohexanone involves mixing Kota stone slurry with activated fly ash, refluxing the paste, separating solid mixture from refluxing unit, calcining mixture, obtaining solid base catalyst, reacting benzaldehyde with cyclohexanone in presence of obtained Kota stone slurry catalyst in a solvent-free medium, carrying out reaction at temperature of 90-120 degrees C and atmospheric pressure for 30-120 minutes, and separating the solid catalyst from reaction mixture by simple filtration method.    USE - Synthesis of alpha , alpha '-dibenzylidenecyclohexanone used as intermediate for producing agrochemical and pharmaceuticals products.    ADVANTAGE - The method enables synthesis of alpha , alpha '-dibenzylidenecyclohexanone in a single step with reduced usage amount of catalyst having excellent thermal stability, handleability, and reusability with respect to three reaction cycles, and high catalytic activity, without requiring solvent, by economical and environmentally-friendly process.    DETAILED DESCRIPTION - Synthesis of alpha , alpha '-dibenzylidenecyclohexanone involves mechanically-activating fly ash by ball milling, thermally-activating fly ash by calcining at 900 degrees C, mixing Kota stone slurry with activated fly ash, refluxing the paste at 110 degrees C for 24 hours under constant stirring, separating solid mixture from refluxing unit, drying mixture at 110 degrees C for 24 hours, calcining mixture at 550 degrees C for 2 hours under static conditions, obtaining solid base catalyst, condensation-reacting benzaldehyde with cyclohexanone in presence of obtained Kota stone slurry catalyst in solvent-free medium by maintaining the substrate to catalyst weight ratio of 10, carrying out reaction at temperature of 90-120 degrees C and atmospheric pressure for 30-120 minutes, separating the solid catalyst from reaction mixture by simple filtration method, washing the catalyst with acetone for removing adhering materials, drying catalyst at 110 degrees C for 24 hours, and calcining the catalyst at 550 degrees C for 2 hours under static conditions.