In the past decade, substantial research has been focused on new energy-saving concepts for lighting and display applications. Organic light-emitting diodes (OLEDs) are the most promising devices for this task, since they consume only a fraction of the energy of conventional, inefficient light bulbs and can be manufactured on thin, flexible, and lightweight substrates. In parallel, the growing interest in the photochemistry of Zn(II) and Cd(II) coordination compounds in the forms of discrete and polymeric species resulted in electroluminescent materials used in OLEDs [1]. The present study aims at the preparation of coordination polymers or MOFs based on a cyclic triimidazole ligand (L), recently investigated by the Italian team for its outstanding properties of crystallization-induced and mechanochromic emission associated with an ultralong room temperature phosphorescence [2]. The strong emission has been explained by short interplanar distances indicative of strong π-π interactions in the ground state, associated with a large interchromophoric π-stacking area and formation of Haggregates. On the way to the coordination polymers with L ligand two mononuclear coordination isomers, [Zn(H2O)6](NO3)2(L)2 (1) and [Zn(H2O)4(L)2](NO3)2(H2O)2 (2) were obtained by one-pot cocrystallization of Zn(NO3)2 .6H2O with L. The colourless crystals with rhombohedral (1) and prismatic (2) shapes crystallize in the triclinic P-1 space group with the close unit cell dimensions: a=8.0765(6), b=9.1056(7), c=10.2014(8) Å, α=71.701(7), β =76.625(7), γ =77.036(7)°, V = 683.56(9) Å3 for 1 and a=7.1668(8), b=8.2481(9), c=11.5772(14) Å, α=89.759(9), β=83.66(1), γ =73.406(10)°, V = 651.57(13) Å3 for 2, which illustrate the more efficient packing for 2. The Zn(II) octahedral coordination cores formulate six water molecules in 1 and four water molecules and two monodentate L ligands in 2 (Figure). The dimeric ligand’s H-aggregates with big π-stacking area and short interplanar separation of 3.25 Å typical for free L ligand are saved in 1 and are replaced by the water…L…NO3 - heteromeric stacks in 2. The study of emissive properties of new compounds is in progress.