Graphene, a two-dimensional material composed of a single layer of carbon atoms arranged in a hexagonal lattice, is one of the most promising materials in nanotechnology. However, structural defects in graphene, which can arise during growth or processing, can significantly affect its electronic and mechanical properties. While defects can be detrimental to performance, they also offer opportunities for tailoring local properties and achieving new functionalities. This review discusses the types and effects of point and line defects in graphene, emphasizing its unique ability to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Defects in graphene can be categorized into point defects (e.g., vacancies, interstitials) and line defects (e.g., dislocations, grain boundaries). Point defects, such as single vacancies (SVs) and double vacancies (DVs), can significantly alter the electronic and mechanical properties of graphene. For example, SVs can lead to the formation of nonhexagonal rings and introduce dangling bonds, while DVs can result in different configurations of pentagons and heptagons. The formation energy of these defects varies, with SVs having higher energy than DVs, making DVs more thermodynamically favorable. Line defects, such as grain boundaries and dislocations, can also influence the properties of graphene. These defects can be generated during crystal growth, irradiation with energetic particles, or chemical treatment. For instance, irradiation with electrons or ions can create point defects by ejecting carbon atoms from their lattice sites. Chemical treatments, such as oxidation or plasma treatment, can also introduce defects by modifying the surface of graphene. The electronic properties of defective graphene are significantly affected by the presence of defects. Defects can introduce localized states near the Fermi energy, altering the electronic structure and transport properties of graphene. For example, Stone-Wales (SW) defects can open a local bandgap in graphene, which may be important for defect-mediated engineering of the local electronic structure. Additionally, defects can influence the reactivity of graphene, allowing for the adsorption of other atoms and the functionalization of graphene surfaces. In summary, structural defects in graphene play a crucial role in determining its properties and potential applications. While defects can be detrimental to performance, they also offer opportunities for tailoring the properties of graphene and achieving new functionalities. Understanding the types and effects of defects in graphene is essential for the development of graphene-based devices and materials.Graphene, a two-dimensional material composed of a single layer of carbon atoms arranged in a hexagonal lattice, is one of the most promising materials in nanotechnology. However, structural defects in graphene, which can arise during growth or processing, can significantly affect its electronic and mechanical properties. While defects can be detrimental to performance, they also offer opportunities for tailoring local properties and achieving new functionalities. This review discusses the types and effects of point and line defects in graphene, emphasizing its unique ability to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Defects in graphene can be categorized into point defects (e.g., vacancies, interstitials) and line defects (e.g., dislocations, grain boundaries). Point defects, such as single vacancies (SVs) and double vacancies (DVs), can significantly alter the electronic and mechanical properties of graphene. For example, SVs can lead to the formation of nonhexagonal rings and introduce dangling bonds, while DVs can result in different configurations of pentagons and heptagons. The formation energy of these defects varies, with SVs having higher energy than DVs, making DVs more thermodynamically favorable. Line defects, such as grain boundaries and dislocations, can also influence the properties of graphene. These defects can be generated during crystal growth, irradiation with energetic particles, or chemical treatment. For instance, irradiation with electrons or ions can create point defects by ejecting carbon atoms from their lattice sites. Chemical treatments, such as oxidation or plasma treatment, can also introduce defects by modifying the surface of graphene. The electronic properties of defective graphene are significantly affected by the presence of defects. Defects can introduce localized states near the Fermi energy, altering the electronic structure and transport properties of graphene. For example, Stone-Wales (SW) defects can open a local bandgap in graphene, which may be important for defect-mediated engineering of the local electronic structure. Additionally, defects can influence the reactivity of graphene, allowing for the adsorption of other atoms and the functionalization of graphene surfaces. In summary, structural defects in graphene play a crucial role in determining its properties and potential applications. While defects can be detrimental to performance, they also offer opportunities for tailoring the properties of graphene and achieving new functionalities. Understanding the types and effects of defects in graphene is essential for the development of graphene-based devices and materials.