In the present study, the nanostructures from curcumin dye, Phthalocyanine (Pc) dye and graphene quantum dot GQD (C30H14), as well as, the nanocomposites which include (GQD/ curcumin, 2GQD/ curcumin, GQD/ Pc and 2GQD/ Pc) are considered to investigate the performances in solar sensation. The geometrical optimization and optical properties of the studied structures are done using the density functional theory DFT and time dependent TDDFT method with B3LYP/6-31G level. Examining the evaluated structures as a sensitizer of dye-sensitized solar cells (DSSCs) by taking the TiO2 electrode and I-/I-3 electrolyte, it was found that the HOMO and LUMO energy levels, charge spatial separations, energy gap, and light harvesting efficiency for GQD/ Pc nanocomposite satisfied the requirements as a sensitizer. Therefore, it is concluded that the GQD/ Pc nanocomposite indicates an equilibrium among the multiple essential factors and it is predicted that it can be preferred as a promising sensitizer in the DSSCs compared with others structures.