A new family of bis(ethylenedithio)tetrathiafulvalene (ET) radical salts has been prepared in the presence of a triangular molybdenum sulfide cluster of formula [MO3S7Br6](2-), which contains highly electrophilic axial sulfur atoms. A systematic change in the experimental conditions yields five different salts, namely (ETA)(2)(ETB)[Mo3S7Br6](2). CH2Br2 (1), (ETA) (ETB)[Mo3S7Br6].1.1CH(2)Br(2) (2), (ETA) (ETB) (ETC) {[Mo3S7Br6]Br}.0.5C(2)H(4)Cl(2) (3), (ET)((n-Bu-4)N)[Mo3S7Br6] (4), and (ET)(Ph4P)[Mo3S7Br6].0.5CH(3)CN (5), where the ET subscript denotes crystallographically independent molecules. The five compounds have been structurally characterized, and all of them crystallize in the triclinic space group P (1) over bar with Z = 2. Lattice parameters (Angstrom, deg) are the following: a = 11.762(4), b = 12.246(4), c = 16,813(6), alpha = 107.572(9), beta = 99.133(7), and gamma = 102.856(8) for 1; a 12.643(3), b 13.370(4), c = 17 936(4), alpha = 103.884(8), beta = 95.013(7), and gamma = 114.396(6) for 2; a 11.907(6), b 12.742(6), c = 22,905(12), alpha = 90.053(15), beta = 79.063(14), and gamma = 75.802(15) for 3; a = 12.787(6), b = 13.653(6), c = 17.543(8), alpha = 68.398(10), beta = 69.911(12), and gamma = 62.377(10) for 4; a = 12.467(5), b = 13.553(6), c = 18,913(8), alpha = 85.378(11), beta = 78.576(11), and gamma = 65.858(9) for 5. Structural data combined with Raman spectral analysis shows that, in salt 1, one-third of the ET molecules, those marked as ETB, are incorporated into the structure as ET2+ and two-thirds as ET+. Bonds distances and Raman frequencies for donor molecules in compounds 2-5 suggest a 1+ charge for all ET molecules, in agreement with the stoichiometries and IR and electronic spectra of these salts. In all cases the various donor-cluster, donor-donor, and cluster-cluster interactions and those involving the solvent molecules give rise to unique arrangements of the donor molecules, A general feature of structures 1-5 is the presence of alternating layers of dimerized organic donor molecules (ET+:ET+) and of inorganic clusters, where the long axis of the donor dimers runs almost parallel to the cluster layer. There is a strong tendency of the combination {[Mo3S7Br6]:ET} to accommodate a third bulky component. Compounds 4 and 5 incorporate [(n-BU4)N](+) or [Ph4P](+), respectively, with no apparent interactions with the ET layers in the solid state. Compound 2 and 4 are semiconductors, while the remaining salts are insulators.