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In light of the increasing interest in organic-organic multicomponent heterostructures on metals, this molecular-scale study investigates prototypical composite systems of ultrathin porphyrin and ionic liquid (IL) films on metallic supports under well-defined ultra-high vacuum conditions. By means of angle-resolved X-ray photoelectron spectroscopy, we investigated the adsorption, stability and thermal exchange of the resulting films after sequential physical vapor deposition of the free-base porphyrin 5,10,15,20-tetraphenyl-porphyrin, 2H-TPP, and the IL 1-methyl-3-octylimidazolium hexafluorophosphate, [C8C1Im][PF6], on Ag(111) and Au(111). 2H-TPP shows 2D growth up to two closed molecular layers on Ag(111) and Au(111), and 3D island growth for thicker films. IL films on top of a monolayer of 2H-TPP exhibit Stranski-Krastanov-like growth and are stable up to 385 K. The 2H-TPP layer leads to a destabilization of the IL films compared to the IL in direct contact with the bare metals by inhibiting the specific adsorption of the ions to the metal surfaces. When the porphyrin is deposited on top of [C8C1Im][PF6] at low temperature, the 2H-TPP molecules adsorb on top of the IL film at first, but replace the IL at the IL/metal interfaces upon heating above 240 K. This exchange process is most likely driven by the higher adsorption energy of 2H-TPP on the Ag(111) and Au(111) surfaces, as compared to the IL. The behavior observed on Ag(111) and Au(111) is identical. The results are highly relevant for the stability of porphyrin/IL-based thin film catalyst systems and molecular devices, and more generally, stacked organic multilayer architectures.