We report one-pot syntheses of chrysene compounds via PtCl2-catalyzed hydrative dimerization of readilyavailable 2-alkynyl-1-acetylbenzenes. This new tandem catalysis comprises an initial selective hydrationof the alkyne, followed by chemoselective dimerization of diketone intermediates. The mechanism ofthis cyclization has been elucidated by 13C labeling experiments as well as isolation of reactionintermediates.