The reaction of Co(OAc) 2 .4H 2 )O and Cu(OAc) 2 .H 2 O with new bis-triazenido proligands, H 2 L, L = CH 2 (C 6 H 4 NNNC 6 H 4 -X-p - ) 2 , X = Me- (a), MeO- (b), in methanol/acetone yields binuclear complexes [ML] 2 , M = Co 2 + (1a, b) and Cu 2 + (2a, b), as green noncrystalline solids. The IR spectra present the three typical vibrations (ν a s , ν s and δ) of the deprotonated triazenido unit (NNN) according to the C 2 v symmetry. The ESR characterisation proves the N 1 N 3 -η 2 , N 4 N 6 -η 2 tetraconnective bis-chelating coordination of bis-triazenido anions and the square-planar symmetry of the MN 4 chromophore. For the cobalt(II) complexes a small rhombic distortion can be mentioned.