For applications such as molecular electronics and spintronics, it is very important to accurately describe the interface between molecular species and the underlying surfaces. In this work, we have used low temperature scanning tunneling microscopy to study the physical and chemical interaction between individual cobalt-tetraphenylporphyrin molecules and a copper nitride monolayer. We have demonstrated that the Cu₃N-Cu(110) system promotes a selective decoupling of the porphyrin macrocycle from the local environment, allowing visualization of the molecular orbitals and vibronic states of the molecule, while maintaining a strong coupling between the Co-d_z² orbital and the substrate. The reverse behavior was observed for adsorption of the same molecule onto a metallic Cu(110) surface. First-principles calculations confirm both the molecular adsorption site and the electronic decoupling of the molecular states from the substrate.