text: The INHIBIT logic gate incorporates a Tb ion in a chelate complex. This two-input logic gate is the first of its kind and displays non-commutative behavior with chemical inputs and a phosphorescence output. Whenever dioxygen (input “1”) is present, the system is quenched and no phosphorescence is observed (output “0”). The second input, H, must also be present for an output “1” to be observed. This is understood from a two-input INHIBIT truth table as included in Table 2.