Several phenyl and naphthyl triflates undergo catalytic cross-methylation with the monomeric and dimeric dimethylaluminum, -gallium and -indium complexes 1a, 1b, 1c, 3a, 3b and 3c in the presence of either PdCl2(PPh3)(2). Pd(PPh3)(4) or Pd(binap)(OAc)(2). 4-Bromophenyl triflate reacts selectively via the triflate function. Structural features of the substrate and the methylating agent, as well as the nature and quality of the palladium catalyst have a considerable influence on the cross-coupling process.