Two kinds of new osmium(II) porphyrin oligomers having tetraarylporphyrins with 3-pyridyl and phenyl groups as axial or a bridging ligands, Dimer-Oblique and cis-Trimer-Oblique were synthesized and characterized by spectral methods. In cis-Trimer-Oblique. atropisomerization caused by the rotation of pyridyl groups was observed by H-1 NMR spectral measurements at room temperature.clear organoaluminum compound {[AlMe2](3)[CH3C(CH2NH)(2)(CH2O)](2)Al} (1) and a trinuclear compound (AlMe2)(2)AlMe[CH3C(CH2NH)(CH2O)(CH2SPh)] (2), respectively. Both compounds were characterized by H-1 and C-13 NMR data, IR, and mass and elemental analysis. Compound 1 was also characterized by single-crystal X-ray diffraction analysis. Compound 1 crystallized in a tetragonal space group P4(1)2(1)2 (No. 92), with cell parameters a = 10.238(2) Angstrom, c = 24.470(2) Angstrom, V = 2565(1) Angstrom(3), Z = 4, and R = 0.060. It appears that the central aluminum atom is surrounded by two tripodal ligands in an octahedral geometry, whereas the other three aluminum atoms act to bridge the two ligands. Compound 2 has a pentacoordinated aluminum center surrounded by two tripodal ligands and one methyl group. The sulfur atoms on the tripodal ligand were not coordinated to the central aluminum atom.