Two　samarium　complexes　with　3-methylbenzoic　acid　(HMeBA　=　3-methylbenzoic　acid)　have　been　hydrothermally　synthesized　directly:　Sm(MeBA)3　1　and　Sm2(MeBA)6(o-Phen)2　2　(o-Phen　=　o-phenanthroline).　1　is　a　one-dimensional　helical　chain　structure.　In　particular,　due　to　the　existence　of　the　second　ligand-o-Phen,　which　includes　three　aromatic　rings　and　has　very　large　steric　hindrance,　2　is　a　zero-dimensional　binuclear　oligomer　and　is　further　assembled　into　an　infinite　chain,　two-dimensional　net　and　three-dimensional　supramolecular　structure　by　the　weak　interactions　of　π-π　and　C-　H···π.　Additionally,　in　order　to　explore　the　structural　characteristic,　luminescence　and　2D-IR　correlation　spectroscopy　containing　temperature-induced　structural　variation　and　magnetism-induced　structural　variation　are　used.　Supplementary　material　is　available　for　this　article.　Go　to　the　publisher＇s　online　edition　of　Synthesis　and　Reactivity　in　Inorganic,　Metal-Organic,　and　Nano-Metal　Chemistry　to　view　the　supplemental　file.　©　2014　Copyright　Taylor　and　Francis　Group,　LLC.