Tandem Friedel-Crafts reaction of arenes and aldehydes under the catalysis of Lewis acid was investigated. Both aromatic and aliphatic aldehydes underwent a tandem Friedel-Crafts alkylation with electron-rich arenes to afford 1,1,1-triaryl/1,1-diarylalkanes in the presence of anhydrous aluminum chloride under solvent-free conditions. The scope, limitation, and mechanism of the tandem reaction were also discussed. (c) 2006 Elsevier B.V. All rights reserved.