Abstract: A series of double ‘cubane’ clusters (Et₄N)₄[(MoFe₃S₄(SR)₃)₂Fe(SR)₆], R=Ph、o-tol、m-tol、and p-tol, were studied with magnetic susceptibility and ¹H NMR. Their magnetic and electronic structures were discussed. Isotropic shifts of both bridging and terminal ligands are mainly from contact interaction. Within a ‘cubane’ unit [MoFe₃S₄],the unpaired electrons are delocalized with strong antiferromagnetic coupling among the paramagnetic metal atoms. Two ‘cu-banes’ and a Fe(SR)6 bridge, form three practically uncorrelated magnetic centers.