The complex [N,N'-ethylenebis(1-phenyl-3-imino-1-butanonato] Mn(Ⅲ) thiocyanate has been synthesized. The title compound Mn(Ⅲ) (bzacen)(NCS) crystallizes in the triclinic system, space group P1, with parameters: a=1.0702(3)nm, b=1.2343(2)nm, c=0.8999(2)nm, α=93.74(2)°, β=97.09(2)°, γ=109.07(2)°, V=1.1078(9)nm^3, Dc=1.377g·cm^-^3, Z=2, F(000)=476, μ=6.85cm^-^1. The final R value is 0.052 for 3205 observed reflections with I≥4σ(I). The coordination geometry around Mn atom is distorted square-pyramidal, the basal plane consisting of two nitrogen atoms and two oxygen atoms from the Schiff base ligand bzacen^2^-, while axial site is occupied by a nitrogen atom from NCS^- group. The packing of the molecules leaves empty channels running through the crystal along the c axis. The shifts of ν~C~=~N, ν~C~=~O and ν~C~=~C to lower frequencies in IR and Raman spectra indicate that the ligand bzacen^2^- has been coordinated to Mn atom through its nitrogen and oxygen atoms. The lines observed at 462cm^-^1 and 399cm^-^1 in Raman spectrum are assigned to Mn-O and Mn-N vibrations, respectively. There are π～π^* transition, d～π^* charge-transfer transitions and d～d^* transition in electronic spectrum. The current potential curve in acetontrile reveals that Mn(Ⅲ) is in stable valence state. The electronic structure was studied by the EHMO calculation.

Key words: INFRARED SPECTROPHOTOMETRY, CRYSTAL STRUCTURE, ELECTRONIC STRUCTURE, SCHIFF BASE, MANGANESE COMPLEX, THIOCYANATO COMPLEX, RAMAN SPECTROMETRY, SPECTRAL PROPERTIES