This article describes the synthesis and spectroscopic (H-1-NMR, UV/vis, resonance Raman) properties of the new complexes (CO)(5)MnRe(CO)(3)(L), (CO)(5)MnRe(CO)(3)(L)Re(Br)(CO)(3) (L = 2,2’-bipyrimidine (BPYM), 2,3-bis(2-pyridyl)pyrazine (DPP)), and (CO)(5)MnRe(CO)(3)(BPYM)W(CO)(4) and the single-crystal X-ray structure of (CO)(5)MnRe(CO)(3)(BPYM)Re(Br)(CO)(3). The crystals are triclinic, space group P $($) over bar$$ 1, with cell dimensions a = 11.819(3) Angstrom, b = 14.957(9) Angstrom, c = 15.792(7) Angstrom, alpha = 64.09(4)degrees, beta = 88.88(7)degrees, gamma = 88.22(8)degrees, and Z = 4. Least-squares refinement on F, for 4620 observed reflections, converged to R = 0.127. The two different metal fragments (CO)(5)MnRe(CO)(3) and Re(Br)(CO)(3) are coordinated to BPYM via Re with Mn(CO)(5) and Br- in a mutually trans position perpendicular to the BPYM plane. An important aspect of this structure is the asymmetric bonding within the bridging BPYM ligand. From the C-N bonds connected to the inter-ring C-C bond, those involving N atoms coordinated to the Re-0 atom of the (CO)(5)MnRe(CO)(3) moiety are longer than those involving the N atoms coordinated to the Re-1 atom of the Re(Br)(CO)(3) fragment. This asymmetry of BPYM is also evident from the H-1-NMR spectrum and is responsible for the occurrence of two absorption bands in the visible region belonging to separate transitions from the two metal fragments to BPYM. It even manifests itself in the resonance Raman spectra by showing resonance enhancement of intensity for BPYM vibrations with slightly different frequencies upon excitation into either of these MLCT bands. This asymmetry is not observed for the corresponding DPP-bridged complex and also not for (CO)(5)MnRe(CO)(3)(BPYM)W(CO)(4). The resonance Raman spectra of the latter compound point to a reversal of the order of the a(u) and b(2u) pi* orbitals of BPYM as compared with the free ligand. The distortion of the BPYM ligand appears to be responsible for a very weak electronic pi interaction between the two metal fragments in (CO)(5)MnRe(CO)(3)(BPYM)Re(Br)(CO)(3) which may thus be viewed as a mixed-valence complex.