Tunable diode laser sensors based on absorption of fundamental vibrational bands of H2O and combination vibrational bands of CO2 near 2.7μm are developed. These bands have stronger absorption linestrengths compared to the bands near 1.5 μm accessed previously with telecommunications diode lasers. The increased absorption strength of transitions in this new wavelength range provides greatly enhanced sensitivity and the potential for accurate measurements in combustion gases with short optical path lengths. Measurement of line position, linestrength, and broadening parameters are carried out for candidate CO2 and H2O transitions in a static cell. Absorption measurements of CO2 and H2O are then made in a laboratory flat-flame burner to illustrate the potential for combustion sensors using this new class of diode lasers.