We present ALMA archival observations of the Flying Saucer (0.5’’) and new NOEMA observations of SSTau042021 (0.3’’). With an inclination $> 85^o$, these two disks are almost perfectly edge-on. We use the tomographic method described in Dutrey et al 2017 to reconstruct the 2D brightness distribution Tb(r,z) of the observed molecular lines (12CO, 13CO, CS, CN, H2CO and HCO+). This new study gives some very interesting and unexpected results. This confirms that edge-on disks are ideal laboratories to provide a direct view of the molecular stratification in proto-planetary disks. This allows a significant improvement for the comparison between chemical models and observations.