A multifunctional bidimensional mixed-valence copper coordination polymer [Cu₂Br(IN)₂]_n (IN = isonicotinato) has been characterized in crystal phase and isolated on graphite surface as single sheets.

Two 2,6-bispyrazolylpyridine ligands (bpp) were functionalized with pyrene moieties through linkers of different lengths. In the ligand 2,6-di(1H-pyrazol-1-yl)-4-(pyren-1-yl)pyridine (L1) the pyrene group is directly connected to the bpp moiety via a C–C single bond, while in the ligand 4-(2,6-di(1H-pyrazol-1-yl)pyridin-4-yl)benzyl-4-(pyren-1-yl)butanoate (L2) it is separated by a benzyl ester group involving a flexible butanoic chain. Subsequent complexation of Fe(II) salts revealed dramatic the influence of the nature of the pyrene substitution on the spin-transition behaviour of the resulting complexes. Thus, compound [Fe(L1)₂](ClO₄)₂ (1) is blocked in its high spin state due to constraints caused by a strong intermolecular π–π stacking in its structure. On the other hand, the flexible chain of ligand L2 in compounds [Fe(L2)₂](ClO₄)₂ (2) and [Fe(L2)₂](BF₄)₂·CH₃CN·H₂O (3) prevents structural constraints allowing for reversible spin transitions. Temperature-dependent studies of the photophysical properties of compound 3 do not reveal any obvious correlation between the fluorescence of the pyrene group and the spin state of the spin transition core.

Fibres of [Ru₂Br(μ-O₂CEt)₄]_n polymer have been isolated on different surfaces under specific conditions, and morphologically characterised by AFM and STM, showing an unexpected helical internal structure.