In the present article, we describe an implementation of the Frenkel exciton model into the open-source OpenMolcas 20 program package. Within the protocol, the monomers can be treated at any multiconfigurational electronic structure level available in OpenMolcas, for instance, RASSCF or (multi-state) RASPT2 . Thereafter, the wave functions of monomers are utilized to compute intermonomer couplings in the spirit of the FEH model.