Samarium (III) tris (2, 6-di-tert-butyl-4-methylphenoxide)(1), which is a highly coordinatively unsaturated complex, was prepared by the reaction of samarium (III) iodide with sodium 2, 6- di-tert-butyl-4-methylphenoxide, and the crystal structure of its acetonitrile complex was determined by X-ray analysis. Complex 1 catalyzed the sequential Michael-Michael-aldol reaction of 3, 3-dimethyl-2-butanone with benzalacetophenone.