A Closed‐Loop Chemical Reaction Network for Autonomous, Dual‐Window Temporal Programming From a Single Fuel Pulse

ABSTRACT Living systems routinely translate single transient inputs into multi‐phase programs of action. To emulate this, we report a closed‐loop chemically fueled reaction network (CRN) based on N ‐benzoyl‐ l ‐cysteine methyl ester‐ N ‐methylpiperazine dithiocarbamate (DTC) that converts one fuel pulse (dithiothreitol (DTT)) into two temporally separated gel windows and then resets to the same molecular precursor, enabling continuous autonomous cycling upon simple refueling. The programmed progression Sol 1 → Gel 1 → Sol 2 → Gel 2 → Sol 1 is enforced by a hierarchical kinetic landscape, which both gates time and closes the loop. The time windows are programmable: pH tunes the onset and lifetime of each gel phase, while fuel reducing strength selectively modulates the first window. Experiments and modeling together confirm dual transients per pulse, molecular‐level reset, and cycle fidelity over >7 iterations. By coupling closed‐loop chemistry with temporal gating, this work lifts fuel‐driven materials beyond the single‐event paradigm, delivering a durable, resettable, and programmable platform for life‐like dissipative functions.