The formation of two metastable complexes (M/L = 1/2 and 1/1) is shown for low temperature co-condensates of europium and samarium vapors with mesogenic ligand 4-penthyl-4'-cyanobiphenyl (5CB). The DFT-calculations based on hybrid B3LYP potential have been carried out to study the equilibrium, structures of complexes. The model structures including one and two metal atoms with antiparallel disposition of ligand molecules are considered. The spectral shifts for ligand CN-group stretching vibrations and the relative thermal stability of the complexes are discussed.