Oepartment of Chemistry, Tripura University, Suryamaninagar-799 130, Tripura, India Department of Chemistry, North-Eastern Hill University, Shillong-793 022, Meghalaya, India Manuscript received 2 January 2007, revised 6 March 2007, accepted 19 March 2007 Manganese(ll) acetate tetrahydrate reacts with N-(2-hydroxy-1-naphthylidcne)glycine (ohgIH2) in methanolic solution in (1 : 3.5) molar ratio yielding the complex, tris[N-(2-oxo 1naphthylidene)glycinato]manganese(lll), [MnIII(ohgIH)3] and its reaction with other oxygen, nitrogen and/or sulphur donors results in the MnIII complexes having compositions [MnIII(ohgI)(L)(X)] [L = salicylate (sal), X = H2O, pyridine (py); 4-nicotinate (nic), X = H2O] and [MnIII (ohgl)(ohdtb)(Y)2].H2O [ohdtb = o- ydroxydithiobenzoate, Y = H2O, py, 3-picoline (3-pic)]. The complexes have been characterized by elemental analysis, molar conductance, magnetic moment, cyclic voltammetry, NMR, electronic and infrared spectral studies. On the basis of UV, IR and NMR spectral evidences, the ligand, N-(2- ydroxy-1- naphthylidene)glycine, exists predominantely in the quinoneamine form and acts as monobasic bidentate and dibasic tridentate ligand in the complexes.