The evidence for direct transmission of π-electron conjugation across a d-electron ferrocene or ruthenocene was previously provided by the exploration of and ruthenocenoporphyrinoids incorporating 1,1'-metallocene. The present work reveals a hitherto unknown feature of metallocenoporphyrinoids. The relevant 1 H NMR spectra of ruthenocenoselenaporphyrin and its protonated forms confirmed the presence of macrocyclic aromaticity. The aromaticity and π-delocalization patterns were visualized using EDDB plots and NICS 2D maps. Remarkably, ruthenocenoselenaporphyrin acts as a monoanionic organometallic macrocyclic ligand, as evidenced by the formation of a heterometallic ruthenium(II)-palladium(II) derivative, providing the rear example of M-C σ-coordination of the metallocene unit in the macrocyclic surroundings.