Density functional theory (DFT) and time-dependent (TD-DFT) computations have been carried out to study the nonlinear optical response of C24S12 and C16S8 sulflowers with lithium atom. The Li interaction surprisingly causes the remarkable first hyperpolarizability enhancement. Also, the HOMO-LUMO gaps of C24S12 and C16S8 sulflowers are significantly narrowed due to the interaction. The Li interaction with these sulflowers is found to be thermodynamically favorable with negative interaction energies. These sulflowers interacted with Li atom could be introduced as innovative nonlinear optical nanomaterial.