Crate chemistry: The inclusion dynamics of molecular boxes has been studied by virtue of the synthesis of the voided ionophilic packing crate [{CpCo(CN)3}4-(Cp*Ru)4] (CP=C5H5 CP*=C5Me5). Numerous ions can then be inserted into the box (see scheme). The box exhibits the highest formation constant known for Cs+ ions. Once inside, ions are insulated from chemical attack, such as amine-deprotonation or H-D exchange.