The combination of the dicopper platform [Cu-2(L)(2)(THF)(2)] (1.2THF)) Wherel H2L, is 1,1'-(1,3-phenylene)-bis-4,4-dimethylpentane-1,3-dione, and 1,4-bis(4-pyridyl)piperatine (bpp), afforded the first example of a one-dimensional polyrotaxane [(1) (mu(2)-bpp)]-[(1)(2)(bpp)(2)]}(n) whose "string" and "bead" are constructed from the same components. The bead of stoichiometry [(1)(2)(bpp)(2)] has a large rectangular cavity of dimensions 7.40 X 15.64 angstrom and is threaded onto a stair-like string of composition [(1) (mu(2)-bpp)](n). The formation of the polyrotaxane is driven by pi-pi stacking between the string and the beads With precise electronic and steric complementarity between these components. A pathway for the formation of the polyrotaxane is proposed.