Elegant construction of metal coordination complexes with specific motifs is a thematic issue since the coordination materials have potential applications such as molecular separation, toxic materials adsorption, molecular containers, ion exchangers, molecular recognition, and luminescent sensors.1-6 Thus, various kinds of framework molecules have been synthesized by the coordinations of metal ions with tailor-made organic tectonics 7-10 even though serendipitous motifs have been frequently formed owing to the presence of unpredictable weak interactions such as hydrogen bonds, van der Waals forces, metal-metal interactions, and π-π interactions. [7][8][9][10][11][12][13][14][15][16][17][18] The molecular structures of multidentate N-donor ligands including flexibility play key roles in the construction of the coordination materials. Recently, we have demonstrated that various silicon-containing pyridyl ligands are useful for the synthesis for desirable skeletal structures since the ligands are adjustable in their potential bridging ability and length, possess flexible angles around silicon, and are conformationally nonrigid. [19][20][21][22][23] On the other hand, dinuclear Cu(II) complexes have been a significant field owing to the following reasons: (i) they can be prepared by the normal methods using bridging ligands, (ii) they provide useful simple models for the study of the magnetic interaction of two unpaired d electrons, and (iii) they are useful models of the biological copper systems. 24 These factors have provided major incentives in the researches of novel dimeric copper(II) complexes. In order to expand the dimeric cupper(II) chemistry, the slow diffusion of Cu(NO 3 ) 2 in methanol with 1,4-bis(dimethyl-3-pyridylsilyl)benzene in dichloromethane was accomplished. Herein, we report a doubly supported cyclodimeric cupper(II) complex with methanol molecules as a sixth ligand.The new ligand, 1,4-bis(dimethyl-3-pyridylsilyl)benzene (L), was prepared by the reaction of 1,4-bis(chlorodimethylsilyl)benzene with 3-bromopyridine according to the literature method (eq. 1). 25 The slow diffusion of Cu(NO 3 ) 2 in methanol into L in dichloromethane produced purple crystals suitable for X-ray crystallography as shown in Scheme 1. Even though the crystals have methanol molecules, they are very stable under an aerobic condition at room temperature. The product was insoluble in common organic solvents such as toluene, benzene, tetrahydrofuran, and acetone, but is slightly soluble in methanol. The product seems to be dissociated in Me 2 SO and N,N'-dimethylformamide. The formation of the product was not significantly affected by the change of reactant mole ratio and concentration, indicating that the compound is a favorable species.(1) X-ray characterization on a single crystal has provided a unique cyclodimeric species of the building block, [Cu-(μ-OMe)(L)(NO 3 )(MeOH)] (Scheme 1). The C 2 symmetric (perpendicular to the center of the Cu, O, Cu, and O plane) crystal structure of [Cu(μ-OCH 3 )(L)(NO 3 )(CH 3 OH)] 2 is...