Based on the above investigations and a recent study of 21carbaselenaporphyrinoids 9 and 10 (Schemes 1 and 2), it is assumed that 21-carba-23-selenaporphyrin 9 can serve as a perfect macrocyclic π-conjugated platform for the coordination to a cyclopentadienyl ruthenium fragment, leading to the formation of the 1,3-metallacenoporphyrin hybrid (Figure ). In contrast to other 21-carbaheteroporphyrins, 21-carba-23selenaporphyrin exists predominantly as a tautomer 9-I with the tetrahedral C(21) carbon atom (Scheme 1). Importantly, 1,3metallocenoporphyrin was postulated as an intermediate complex in the synthesis of meso-tetraaryl-21-carbaporphyrin. Herein, we report the synthesis and characterization of ruthenocenoselenaporphyrin 11 and its palladium complex 15. Importantly, these hybrid carbaporphyrin-ruthenocene molecules indicate the direct transmission of π-electron conjugation across the 1,3-ruthenocene bridge. Significantly, the macrocyclic aromaticity is influenced by protonation or metal coordination in the metallocenoporphyrin cavity.