CO laser emission at 5 μm was observed in the flash photolysis of the mixtures of NO and CHBr3 in vacuum uv, in the presence of a large amount of SF6. About 32 transitions ranging from 6 → 5 to 3 → 2 were identified. The dependence of laser intensity upon the total pressures of various mixtures, the partial pressure of NO, and flash energy have been examined. These observations plus the results of gas analysis allow us to conclude that the primary pumping process in the CHBr3-NO system is the following fourcentered reaction: CH + NO → CO† + NH (4a),*Delta;H°4a = -105 kcal/mol. The possibility of occurrence of other side reactions was also discussed.