Broadband N-2 vibrational coherent anti-Stokes Raman scattering (VCARS) thermometry was performed along the nozzle centerline of counter-flow diffusion flames. Fuel mixtures consisted of varying percentages of H-2 in N-2 and the oxidizer was air. We investigated the influence of varying the percentage of H-2 in the fuel stream on the temperature profiles along the nozzle centerline. Measurements were performed, with varying global strain rates, both near and far from flame extinction. One-dimensional simulations, performed using Combustion Simulation Lab (COSILAB) software, show that the temperature profiles are relatively insensitive to the nozzle exit centerline velocity; implying that the 1-D simulations provide an excellent approximation of the real temperature profiles along the nozzle centerline. Various chemical mechanisms were employed within the COSILAB framework for comparison against VCARS temperature measurements. Simulations were also performed to evaluate the influence of thermal diffusion and nitrogen chemistry on nozzle centerline temperature profiles. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.