hydrogen-bonding interactions between rings 2a and 2b and rods 1a and 1b. The rods contain a binding site for the ring as well as a stimulus-responsive diazo group, both of which are conformationally constrained in parallel by connecting them to a rigid xanthene skeleton. The transisomer of 1a bearing a rigid binding site cannot form the pseudorotaxanes with the rings 2a and 2b because the neighboring