The reactor design is documented in refs and briefly explained here. The flow diagram of the reactor is shown in SI Fig 1 . The continuous-flow scCO2 reactor is engineered to operate within a temperature range of 298-873K (25 -600 °C) and a pressure range of 0.101 -30 MPa. The synthesis process involved combining two unheated precursor streams, i.e., metal and organic precursors, with a heated scCO2 in the counterflow mixing section to facilitate fast mixing and heating of the reactants, see SI Fig 2 . After exiting the counter flow reactor section, the effluent rapidly cooled to ambient temperature and passed through a back pressure regulator. The reaction products are retained in the liquid phase while the CO2 is naturally aspirated into the fume hood.