The reactions of trimethylhydroquinone with isoprenoid allylic alcohols catalyzed by a Pentasil type zeolite in the H-form gave trimethyl-1,4-benzoquinones with the corresponding isoprenoid group, which were subsequently transformed into the target Delta(3)-chromenes oil treatment with pyridine. Partial ozonolysis of chromenes proceeded selectively at the Delta-bond of the side chain, resulting in the corresponding chromenes with an omega-carbonyl group.