Chemically reactive nitrogen tetroxide (N2O4 ⇌ 2NO2 ⇌ 2NO + O2) is discussed as a possible working fluid for power-producing thermodynamic cycles. Computation of the thermodynamic properties of the dissociating N2O4 system in liquid and gas phases is based on Soviet sources, since the most extensive research has been carried on at the Institute for Nuclear Energy in Byelorussia, where N2O4 is proposed as a coolant for fast-neutron gas reactors. Kinetics of the chemical reactions are considered by comparison between cycle parameters with equilibrium working fluid in all plant components and computations with frozen second reaction in the turbines. The results of the research, and the pros and cons of the system from the thermodynamic point of view, are discussed in the conclusion.