Scientists have designed a host-guest system using a non-equilibrium kinetically trapped state for on-demand and time-programmable control of molecular functions, and synthesized a macrocyclic metallohost that has anion caps at both sides of the cation-binding site. The anion caps effectively inhibit the guest uptake/release so that we can easily make a non-equilibrium kinetically trapped state. Guest exchange to a more stable state is significantly accelerated by exchange of the anion caps in an on-demand manner.