Using Monte Carlo simulations, we study the effect of the Ruderman–Kittel–Kasuya–Yosida (RKKY) interactions in a bilayer olympicene structure, with mixed spins (σ = 3/2 and S = 2) in the Blume–Capel model. The studied system is formed by two magnetic layers (N1 and N2), separated by a number of non-magnetic layers (NM). We first elaborate the ground-state phase diagrams and then we found that from 4 × 5 = 20 phases possible, only 12 configurations are found to be stable. For low reduced temperature values, the partial magnetizations are found to be in good agreement with the corresponding ground-state phase diagrams. The critical temperature is displaced towards lower temperatures. This is due to the fact that the increasing of the number of non-magnetic layers increases the effect of the RKKY interaction. We have interpreted the behaviors of the magnetic hysteresis for this model.