K1-K2 color magnitude diagram for 38 of the 39 objects in the ExoGRAVITY Spectral Library. AMES-Cond and AMES-Dusty evolutionary tracks at an age of 20 Myr (solid lines) and 100 Myr (dashed lines) are plotted in the background and mid-M-type to late T-type objects from the SpeX Prism Libraries are shown for reference. HD 167665 b is missing from the plot because its methane absorption is strong, thus yielding only an upper flux limit in K2.