The rich chemistry of organic-inorganic metal halide hybrids has enabled the development of a variety of crystalline structures with controlled morphological and molecular dimensionalities. Here we report for the first time a single crystalline assembly of metal halide clusters, (C9NH20)7(PbCl4)Pb3Cl11, in which lead chloride tetrahedrons (PbCl42-) and face-sharing lead chloride trimer clusters (Pb3Cl115-) cocrystallize with organic cations (C9NH20+) to form a periodical zero-dimensional (0D) structure at the molecular level. Blue light emission peaked at 470 nm with a photoluminescence quantum efficiency (PLQE) of around 83% was realized for this single crystalline hybrid material, which is attributed to the individual lead chloride clusters. Our discovery of single crystalline assembly of metal halide clusters paves a new path to functional cluster assemblies with highly tunable structures and remarkable properties.