HF infrared stimulated emission was observed from flash-initiated CHFCl2-NO and CH2FCl-NO mixtures above 165 nm. Several lines were detected between and (1 → 0) in the CHFCl2system, while only (1 → 0) lines were observed in the CH2FCl system. Addition of D2generated DF emission in the former system, whereas it was absent in the latter. Detailed parametric study, including the mass spectrometric analysis of flashed products, led us to conclude that the principal laser-pumping reaction is CHF + NO → CHFNO → HF + CNO. Other possible side reactions in these systems are discussed. No laser emission was detected from flashed CHF2Cl-NO mixtures under the same experimental conditions.