UV photolysis of CpMn(CO)(3) (Cp = C5H5) in near critical liquid N2O at room temperature in both static and flow reactors leads to the formation of CpMn(CO)(2)(N2O) identified via v(C-O) and v(N2O) IR bands, the latter being recorded in low temperature polyethylene (PE) experiments. CpMn(CO)(2)(N2O) has a lifetime of ca. 5 min at room temperature in near-critical N2O and appears to have two decay pathways one of which leads to CpMn(CO)(2)(N-2), possibly via O-transfer.