A new cluster of formula {[Mo3(μ3-S)(μ-S)(μ-S2)2(dtp)3(μ-OAc)][Mo3NiS4(dtp)3(μ-OAc)(CH3CN)]} (1; dtp = diethyl dithiophosphate; OAc = acetate) comprising the novel Cs-symmetrized Mo3(μ3-S)(μ-S)(μ-S2)2 structural type covalently attached to a cubane-type Mo3NiS4 core has been isolated and fully characterized. The reaction of a 2 m HCl solution of [Mo3S4(H2O)9]4+ with an excess of potassium diethyl dithiophosphate and acetic acid in the presence of the [Mo3(NiCl)S4(H2O)9]3+ cluster afforded a mixture of products encompassing different Mo3Sx (x = 4–7) cluster cores from which the Mo3(μ3-S)(μ-S)(μ-S2)2 structural type has been isolated in analytically pure form as a Mo3NiS4 adduct. The robustness of the aggregate 1 was also retained in solution as judged by ESI-MS and 31P NMR techniques. Single-crystal X-ray analysis revealed in detail the complementary association of the newly formed Mo3(μ3-S)(μ-S)(μ-S2)2 entity and the Mo3NiS4 cluster in which μ-S sulfide ligands and μ-S2 disulfide ligands act as nucleophilic and electrophilic functional groups, respectively, towards the Mo3NiS4 cube through directional Ni–S covalent bonds and short S···S contacts (below 3.3 Å).