Library design for drug screening is one of the key steps in drug discovery (Figure and 2). Library design is the most time-consuming process in drug discovery since there is no target or ligand at the beginning of the drug discovery. The most logical way to define a target library is since the possible target number is significantly lower than possible ligands and drug candidates. A library with a target-focused approach refers to a compilation of chemicals that have been intentionally created or constructed to target a protein or protein family specifically. The rationale behind screening such a library is based on the notion that a reduced number of compounds is required to identify hit compounds. Moreover, it is commonly observed that there is a higher rate of successful hits when comparing the screening of diverse sets. Additionally, the hit clusters resulting from a successful focused library screening campaign typically display transparent structureactivity relationships, which aid in the subsequent analysis and investigation of these hits ( ). The library design procedure for drug and target screening encompasses many crucial elements to guarantee the inclusion of a wide-ranging and all-encompassing assortment of probable therapeutic candidates. The process commences with the choice of primary constituents, which are diminutive, structurally diverse molecules employed as the fundamental basis for the collection. Subsequently, these fundamental components are merged in different manners during the phase of library formation, resulting in a wide range of chemical compounds. Subsequently, the library undergoes global propagation and the establishment of a collection of diverse species, wherein various molecular variations are methodically generated and organised. Subsequently, these species undergo testing to determine their capacity to attach to the designated receptor, thereby identifying potential candidates that show promise for subsequent advancement. The technique is recursive, where the successful binding species guide the selection of new building blocks, thus continuously improving and enlarging the library for succeeding screening cycles ( ).