The synthesis of a tin sulfide cluster array, denoted Sn₄S₆-Y, using the quantitative sequential surface anchoring and reaction of tetramethyltin with hydrogen sulfide (metal organic chemical vapor deposition, MOCVD, reagents) within the supercages of acid zeolite-Y is detailed. The tethered methyltin species and their transformation to the encapsulated tin sulfide clusters are elucidated through gravimetry, coupled with mid-IR and ¹¹⁹Sn Mössbauer spectroscopy. Transmission electron microscopy (TEM) and Rietveld refinement of synchrotron powder X-ray diffraction (PXRD) data show that the clusters are internally confined and homogeneously dispersed in the supercages of the host zeolite, while optical spectroscopy show a cluster size dependent blue-shift of the absorption edge with respect to the bulk tin sulfide phase. A geometry is proposed for the encapusulated Sn₄S₆-Y cluster.