We simulate the 2DES of the N -molecule HTC system for various N at a fixed cavity loss rate Γ c = 10 meV. The molecular parameters are kept the same as in the linear spectra simulations. Due to the inclusion of doubly excited subspace, the total number of electronic states now scales as O N 2 . Fig. shows the pure-absorptive 2DES for various N at t 2 = 0 fs for a fixed Rabi splitting.