The syntheses and structures of a [2×1+1×2] cocrystal [{Cu IIL1NaI (H2O) 2}{Cu IIL1}2](NO3) (1) and [3×1+5×1] cocrystal [{(CuIIL1) 2KI}(NO3)] · [{(CuIIL 1)3KI 2 (μ-NO3)} (NO3)] · 0.2H2O (2) derived from the hexadentate Schiff base compartmental ligand N, N′-ethylenebis(3- ethoxysalicylaldimine) (H2L1) are described. Compounds 1 and 2 crystallize in triclinic P1 and monoclinic P21/c systems, respectively. The structure of 1 consists of the [CuIIL 1?aI (H2O) 3]+ cation and two mononuclear [CuIIL1] moieties. In the dinuclear [CuIIL1?aI (H2O) 3] + cation, the metal centers are doubly bridged by the two phenolate oxygen atoms. Each of the two coordinated water molecules of the dinuclear unit is encapsulated in the O4 cavities of the two mononuclear [Cu IIL1] moieties resulting in the formation of a [2×1+1×2] cocrystal. In compound 2, one trinuclear double-decker system [{(CuIIL1)2KI}(NO 3)] and one pentanuclear triple-decker system [{(Cu IIL1)3KI 2 (μ-NO 3)}(NO3)] are cocrystallized. Evidently, compound 2 is a [3×1+5×1] cocrystal. Structural resemblance of 3d metal ions with Na(I) and a rare example of double-decker-triple-decker cocrystal are the major outcomes of the present investigation. © 2009 American Chemical Society.