Treatment of Zr(NEt,), with the free-base porphyrins 5,10,15,20-tetraphenylporphyrin (H,TPP) or 2,3,7,8,12,13,17,18-octaethylporphyrin (H,OEP) gives the transition-metal bis(porphyrinat0) complexes Zr(TPP), and Zr(OEP),. The hafnium analogue Hf(OEP), may be prepared similarly from Hf(NEt,),. The complexes have been characterized by UV-vis and ‘H NMR spectroscopy, and the molecular structure of Zr(TPP), has been determined crystallographically. The Zr-N distances of 2.40 (I) A and the porphyrin-porphyrin interplanar spacing of 2.56 A are the shortest such distances in all known M(porphyrinato), complexes. The cyclic voltammograms indicate that Zr(TPP), and Zr(OEP), each undergo two oxidations and two reductions; the redox potentials suggest that there is significant overlap between the r-systems of the two porphyrin rings. Chemical oxidation of the Zr(porphyrinato), complexes with phenoxathiinylium hexachloroantimonate has led to the isolation of the *-radical-cation complexes [Zr(TPP),+] [SbCIL] and [Zr(OEP),+] [SbC16-]. The UV-vis, near-IR, EPR, and IR spectra of these cations are consistent with oxidation of the porphyrin-porphyrin r-system; most notable are the unusually high energy near-IR bands at 11 IO and 962 nm in the TPP and OEP complexes, respectively. The high energy of these bands with respect to those of other [M(porphyrinat~)~+] cations with larger metal atoms again can be rationalized on the basis of unusually strong overlap between the r-systems of the two porph rin rings. Crystallographic data for Zr(TPP),CSH,,: monoclinic, space group C2/c, with (1 = 21.183 (3) A, b = 21.263 (4) 1, c = 18.688 (3) A. B = 124.57 (l)”, V = 6930.9 A’, Z = 4; RF = 0.077 and RwF = 0.083 for 1578 independent reflections with I > 34).