The next generation of infrared atmospheric sounding interferometer, IASI-NG, will be put into orbit soon. It contains twice more channels than it predecessor IASI. Beside the awaited improvements for numerical weather prediction (NWP), our study aims at evaluating the benefits of IASI-NG radiance assimilation in a chemistry-transport model (CTM) for ozone, compared to IASI. As IASI-NG is not yet in orbit, we used an Observing System Simulation Experiments method (OSSE) both to simulate IASI and IASI-NG synthetic data and to evaluate the impact of their assimilation. The selected time period ranges from 15/05/2019 to 31/08/2019. Our OSSE framework uses the CTM MOCAGE developed at Météo-France, which models both stratosphere and troposphere, over the globe. The ozone spectral band in the long wave band is 980 – 1100cm-1; with 468 channels for IASI, and 936 channels for IASI-NG. We carefully evaluated the ozone Jacobians for all channels in this band, over various scenes. This helped us to reduce the spectral band to 993 – 1069 cm-1, counting 608 IASI-NG channels and 304 IASI channels. RTTOV has been used as a radiative transfer model in this study, both for Jacobian computation and for the direct assimilation of radiances. After having created the synthetic observations from the Nature Run for both IASI and IASI-NG, we evaluated their differences with the Control Run, in order to evaluated their characteristics for assimilation. Then, assimilation trials of IASI and IASI-NG synthetic radiances will be evaluated to assess the benefits of IASI-NG compared to IASI for ozone assimilation. Our presentation will show these impacts, using various assimilation settings.