Clusters perform as a bridge between the gas phase and liquid bulk materials. Classification of clusters into elemental or compound clusters and metallic or non-metallic characteristics comprises by the composition and concentration of substitutions. There are three main categories of existing clusters, discrete clusters, magic cluster, and Nano phase materials. Investigation of small clusters is important in the material sciences because it introduces new phases of solids and characteristics interfaces having tunable features. Clusters predict the growth mechanism of the thin surfaces, nanomaterial’s as well as bulk. Characteristics of the clusters based on the material include geometry as well as periodic crystallography. Clusters are helpful in the field of solid state physics; the cluster structures easily detect defects present in the crystals. Within the finite cluster structure, impurity atom interacts with the nearly present cluster atom that seems to be a good model for the periodic band calculation that performed without boundary conditions. Moreover, the optoelectronic properties of cluster allow top use in computers and disk storage devices of a new generation. Shell structure of clusters comprises magnetic properties and energies that resembled by the atomic nuclei, explore more in the nuclear research. Clusters have been considered as the agitated materials since its versatile properties provide a bridge between different fields of physics. Properties of clusters are entirely different from the bulk material such as metals behaves as semiconducting materials, brittleness of materials converts into malleable. Clusters could be described in two categories that is metallic clusters as well as non-metallic clusters based on the type of atoms that are combined to form the clusters. The investigation of the molecular clusters provides a rapid theoretical as well as computational plan in order to approximate the properties of the materials because clusters contains the specific characteristics and act as building blocks of the materials falling in the range of nano, micro as well as in the bulk materials. It has specific applications in catalysis as it has prime applications in the materials adsorbed on the surface. The building blocks of matter commonly found in nature are either atoms or molecules. Depending on the chemistry of the atoms, the ambient pressure, and temperature, the atoms arrange themselves in well-defined arrays to form different crystal lattices. The properties of these materials often depend strongly on how the atoms are arranged. Molecular crystals, on the other hand, exhibit unique properties because molecules, and not atoms, form the building blocks. Like molecular crystals, it is expected that size-selected cluster-assembled materials may possess unique properties hitherto unknown. The central question is how to design and synthesize stable clusters. The criteria depend on the nature of bonding that exists within a cluster. In clusters of simple metals, as outlined previously, the stability is governed by the electronic shell structure. In covalently bonded clusters such as those of C and Si, the atomic arrangements are important for stability. It is also possible to form stable compound clusters by using suitable alloying techniques. In the following, we discuss these cases through illustrative examples. Systematic variation in properties arises due to unusual cluster structures and often effects of boundaries and quantum confinement. In the clusters the magnitude of band gap varies with the composition and size of the cluster atoms. Recently, heterometallic clusters become the demanding materials in the electrocatalysis, photocatalysis, optoelectronic, microelectronic devices. Clusters are attractive materials due to their fascinating properties and offer research activities of interdisciplinary nature. The cluster science provides liberty to prepare new materials and tune the properties for different applications. The clusters behave entirely different from those of bulk materials; metals act like semiconductors and brittle materials transforms into malleable ones. The electronic and optical properties, especially mechanism of charge transfer and electronic transitions are strongly dependent upon these features. The flexibility of tailoring these parameters gives access to infinite possibilities. The metal oxides clusters are extensively used for energy storage applications, batteries, water splitting, catalysis etc.