The approach presented here is solely based on quantum-chemical calculations and thus does not rely on any empirical parameters. If necessary, all approximations within the L-VSCF/L-VCI approach can be alleviated by (a) using a more reliable methods for the quantum-chemical calculations in the construction of the potential energy surface, (b) using a more complete representation of the potential-energy surface by including additional modes and/or by extending the number of n-mode potentials that are calculated explicitly, and (c) by extending the size of the expansion space in the L-VCI calculations, albeit each of these will increase the required computational effort. We believe that the efficient protocol applied here provides a reasonable starting point for the prediction of 2D IR spectra in the most common cases, as demonstrated by the examples considered here.