Three new complexes containing Mn^II₂Mo^III zigzag chains have been synthesized and structurally characterized. The crystal structure of complex 3 consists of two linkage isomers of the Mo^IIIMn^II₂ chains, which correspond to 1 and 2, respectively. Both complex 1 and 3 show slow magnetic relaxation behavior with an energy barrier of Δ/k_B = 69.5 K and 68.8 K, respectively, whereas complex 2 is a simple paramagnet. The linear apical Mo^III–CN–Mn^II pairs provide the required magnetic anisotropy for the slow magnetic relaxation.