Complex cis-[Mn(CO) 4 (2-S-C 4 H 3 S) 2 ]was employed as a metallo chelating ligand to synthesize [(CO) 4 Mn(µ-2-S-C 4 H 3 S) 2 Ni(µ-2-S-C 4 H 3 S) 2 Mn(CO) 4 ] (1) with a square planar Ni IIthiolate core. The longer Ni II ‚‚‚Mn I distances and electronic population of nickel(II) (d 8 ) are adopted to rationalize the construction of complex 1. Cleavage of the Mn I -S bond in complex 1 by an incoming tridentate metallo ligand fac-[Fe(CO) 3 (ER) 3 ] -(E ) S, R ) C 4 H 3 S; E ) Se, R ) Ph), followed by a thiolate group ([2-S-C 4 H 3 S] -) rearranging to bridge two metals, led directly to the anionic [(CO 3)) with a homoleptic/heteroleptic hexachalcogenolatonickel(II) core, respectively. Dropwise addition of cis-[Mn(CO) 4 (2-S-C 4 H 3 S) 2 ]to the anionic 2 in THF resulted in formation of a linear trinuclear complex [(CO) 3 Mn(µ-2-S-C 4 H 3 S) 3 Ni(µ-2-S-C 4 H 3 S) 3 Mn-(CO) 3 ] 2-(4) possessing a homoleptic hexathiolatonickel(II) core. It seems reasonable to conclude that the d 6 Mn(I) [(2-S-C 4 H 3 S) 3 Mn(CO) 3 ] 2fragment is isolobal with the d 6 Fe(II) [(ER) 3 Fe(CO) 3 ]fragment in complexes 4, 3, and 2.To our knowledge, a few examples of complexes containing a homoleptic hexathiolatometal core or hexaselenolatometal core are reported and characterized by X-ray crystallography. 3 Recent work in this laboratory showed that cis-[Mn-(CO) 4 (ER) 2 ]and fac-[Fe(CO) 3 (SePh) 3 ]complexes are useful in the syntheses of heterotrimetallic Mn(I)-Co-(III)-Mn(I)-chalcogenolate complexes [(CO) 4 Mn(µ-ER) 2 -Co(CO)(µ-E′R) 3 Mn(CO) 3 ] (E ) E′ ) Te, R ) Ph; E ) Te, E′ ) Se, R ) Ph; E ) E′ ) Se, R ) Me) with a unique Co(III)-CO bond, 4 and [(CO) 3 M(µ-SePh) 3 M′(µ-SePh) 3 M-(CO) 3 ] -1/0 (M ) Mn, M′ ) Co; M ) Fe, M′ ) Fe, Cd, Zn, Ni) with a homoleptic hexaselenolatometal core. 3b,5 In these reactions, the complexes fac-[Fe(CO) 3 (SePh) 3 ]and cis-[Mn(CO) 4 (ER) 2 ]act as potential "chelating metallo ligands" and selenolate ligand-transfer reagents. 5c,6 A recent report on distorted square planar [Ni(CO)-(SPh) n (SePh) 3-n ] -(n ) 0, 1, 2), in preparations of the biomimetic nickel-site structure of [NiFe] hydrogenases