Treatment of 21-carbaselenaporphyrin 9 or its palladium complex 14 with [RuCp*(CH3CN)3][PF6] in dichloromethane at 293 K resulted in the η 5 -coordination of a [RuCp*] + fragment to the cyclopentadiene ring of 9 or 14. This led to the formation of ruthenocenoporphyrin 11 (Scheme 1) or bimetallic palladium(II) ruthenocenoporphyrin 15 (two stereoisomers, Scheme 2) with yields of 62% and 96%, respectively. Palladium(II) 21carbaselenaporphyrin 14 was synthesized on an NMR scale by attentive titration of the corresponding 21-carbaselenachlorin complex 13 with a saturated solution of DDQ in [D]chloroform (Scheme 2). Palladium(II) complexes 12 and 13 were obtained in the reaction of 21-carbaselenachlorin 10 with PdCl2 in DMF at reflux with 5% and 39% yields, respectively (Scheme 2; see SI). The selective formation of complex 13 with a yield of 58% was observed in a mixture of CHCl3/CH3CN used as a solvent. The coordination of the [RuCp*] + moiety to the cyclopentadiene ring of 9 has been confirmed by X-ray diffraction studies (Figure ). The macrocyclic ring adopts a nearly planar conformation. The planes of the macrocyclic cyclopentadienyl and the pentamethylcyclopentadienyl rings are almost parallel (the dihedral angle is equal to 4.5°). The distances between the Cp*, Cp ring planes, and the ruthenium ion are 1.81 and 1.83 Å, respectively. These values are slightly longer than those observed in the corresponding RuCp*-polyarene complexes (ca.