The preparation, X-ray crystal structures, and magnetic properties of four new rod-shaped hexanuclear Mn clusters [Mn 6 (O 2 CCH 3 ) 6 (EdeaH) 2 (tmp) 2 ] (1), [Mn 6 (O 2 CCH 3 ) 6 (mdeaH) 2 (tmp) 2 ] (2), [Mn 6 (O 2 CCF 3 ) 6 (teaH 2 ) 2 (tmp) 2 ]·2MeCN (3) and [Mn 6 (O 2 CPh) 6 (EdeaH) 2 (tmp) 2 ]·2Et 2 O (4), where teaH 3 is triethanolamine and tmpH 3 is the tris-hydroxymethyl propane ligand, are reported. DC magnetization data along with AC magnetic susceptibility studies show that these complexes have weak antiferromagnetic coupling, appreciable magnetoanisotropy, and ground states of up to S=4. Though all four complexes show a frequency-dependent out-of-phase signal in the AC susceptibility, a characteristic of single-molecule magnets (SMMs), only complexes 1, 2, and 4 are likely to be SMMs with ground states ranging from S=2 to S=4. Complex 3 shows the weakest AC signal and the lowest spin ground state of S≈1, likely due to small structural differences and intermolecular interactions.