This workshop focusses on the modelling and mechanistic questions related to bidirectional catalysis. Whereas many catalysts work in the two directions of the reaction, bidirectional synthetic molecular redox catalysts are scarce. In enzymology, there has been much interest in trying to elucidate what makes a particular enzyme faster in one direction (a property sometimes called the “catalytic bias”). Related to this question is how much free energy is required to kick off catalysis and what makes the so-called “reversible catalysts” function at a fast rate even close to equilibrium, a property that is needed to design energy efficient devices. Examining experimentally the relations between catalytic rate and driving force is more difficult with a biological motor than with a molecular or a surface redox catalyst, but the same concepts apply. This workshop aims at bringing together people from different fields (surface catalysis, molecular catalysis, molecular machines) to clarify the overlaps, see how much knowledge can be transferred across disciplines, and describe recent advances in the use, design, benchmarking and kinetic modeling of bidirectional catalysts.