The synthesis of novel dinuclear lanthanide complexes with formulas [(LnL₃)(LiL)(MeOH)] (1–3) and [(LnL₃)(LiL)(H₂O)] (4–6) (Ln = Eu(III), Tb(III), Dy(III)) based on functionalized lithium β-diketonate (LiL) is reported. The coordination environment of the Ln(III) ion is formed by oxygen atoms of both the 1,3-dicarbonyl moiety and the acetal group. Depending on the solvent used for the crystallization, methanol or water molecules participate in the coordination with Li(I) ions affecting the crystal structure of complexes. In contrast to [(LnL₃)(LiL)(H₂O)] 4–6, a series of complexes [(LnL₃)(LiL)(MeOH)] 1–3 showed mechanoluminescence properties, thereby demonstrating the relationship between the observed optical properties and crystal packing architecture. The magnetic measurements of [(LnL₃)(LiL)(MeOH)] 1–3 revealed SMM behavior of [(DyL₃)(LiL)(MeOH)] 3 at low temperatures (U_eff is 37.7 cm⁻¹).

High temperature coupling of 6-aryl-5-cyano-3-(pyridin-2-yl)-1,2,4-triazines with 2-amino-4-aryloxazoles proceeds as the inverse demand Diels–Alder reaction between the oxazole moiety as dienophile and the 1,2,4-triazine moiety as diene to construct new 4,5-diaryl-6-cyano-3-hydroxypyridin-2-yl fragment. A reaction mechanism is proposed, and the structure of the key-product is proved by the X-ray diffraction analysis.

Based on ‘1,2,4-triazine’ methodology, a new lanthanide(iii) ligand, 5-(4-dodecyloxyphenyl)-2,2’-bipyridine-6’-carboxylic acid, was synthesized, and its luminescent europium(iii) complex was prepared. The solubility in organic solvents for both the ligand and its europium complex was provided by the presence of a long aliphatic dodecyl moiety. The photophysical properties of the europium(iii) complex were examined, the fluorescence quantum yield and the europium cation luminescence quantium yield were determined.