Unique properties and perfect structures of fullerenes and carbon nanotubes (CNTs) predetermine their great influence on nanotechnologies. These nanoclusters demonstrate exceptional mechanical, physical, chemical, electronic and optical properties and have attracted enormous attention from researchers worldwide [1-7]. Graphene, a planar sheet of sp2 bonded carbon atoms, is the fundamental component of graphite and carbon nanotubes. The discovery by Geim and Novoselov in 2004 [8] generated intense research activity on graphene. Sophisticated low-dimensional characteristics and exceptional mechanical properties have given rise to many technological applications of pristine graphene in various fields. Its use in electronic and optical devices, energy storage systems and composite materials, chemical sensors and drug delivery has been suggested [9-16]. Soon after, the chemical functionalization of graphene became a focus of interest in modern physics and chemistry [11]. The main motivations for these experimental and theoretical studies were the modification of electronic properties by modifying the band gap, the potential use of functionalized graphene for hydrogen storage, the search for techniques to massively produce "cheap" graphene by chemical reduction of graphene oxide, oxidation and subsequent decompression of graphene as a method to create graphene nanostructures of a certain size [17-20] . However, the reactivity of graphene as a planar sheet is much worse than that of CNTs and fullerenes. Therefore, only a few functionalization techniques have been transferred from fullerene chemistry to graphene chemistry, such as azo, aryne and nitrene additions [21–23], Claisen rearrangements [24], 1,3-dipolar and Diels-Alder cycloadditions [25, 26].Carbenes (CR2, R = H, ...... half of the paper ...... rest to consider the structural changes in graphene influenced by dichlorocarbene. The influence of the position of the attached carbene species on the structure of graphene is also an important question. Furthermore, as far as we know, researchers have made no attempt to ascertain what influence solvents offer on the binding energy of carbenes and. on the band gap of functionalized graphene As described in the previous paragraphs, the functionalization of nanotubes and fullerenes with carbenes has been of importance, taking into consideration the significance that graphene reveals nowadays, here we report a comprehensive study. on density functional theory on CCl2 functionalization of finite-sized graphene sheets, focusing on equilibrium structures of CCl2. -attached graphene and effects of attached dichlorocarbene on the electronic properties of graphene.