Abstract Two manganese complexes containing 4,4′-bipyridine and methyl benzoate as ligands have been prepared and crystallized by solvent evaporation method in DMF. The single crystal X-ray crystallographic analyses reveal that the complexes crystallize in monoclinic system. Crystal of 1 [Mn2(4,4′-bipy)2 (o-MBA)4]n has space group of P21/c with unit cell parameters of a=17.508(Å), b=11.6229(Å), c=27.983(Å), β=128.123°, V=4.4797nm3, empirical formula: C52H44Mn2N4O8, Mr=962.79, Z=4, Dc=1.428g/cm3, μ=0.625mm−1, and F(000)=1992. The crystal of 2 [Mn (4,4′-bipy)(m-MBA)2]n belongs to space group C2/c with a=16.079(Å), b=11.652(Å), c=24.887(Å), β=92.02°, V=4.660nm3, empirical formula: C26H22MnN2O4, Mr=481.40, Z=8, Dc=1.372g/cm3, μ=1.179mm−1, F(000)=1992. The weak interactions in structures are observed from the X-ray crystallographic data. These include the CH⋯O hydrogen bonds, π–π stacking and CH⋯π interactions found in 1. The different strength of intermolecular interaction in the structures is reflected on their different thermal stability of the two complexes measured by thermal gravimetric analysis and the 2D-IR correlation spectroscopy. The study of weak interactions is meaningful to provide supporting data for potential application in molecular biology.