Triple-stranded cluster helicates with heptametallic dicubane cores are synthesized by entrapping metals in the cavities of linear triple helicates based on a C-2-symmetrical hexadentate Schiff-base ligand of ortho-substitued biphenol. The helicates are stable in both the solution and solid states, and the copper species could selectively catalyze the oxidation of C-H bonds of alkanes to ketones.