▎ 摘　　要

In the donor-bridge-acceptor [NH2-graphene quantum dot (GQD)-NO2] system, we found that, for GQDs with the same number of carbon atoms, changing the shape of the GQDs not only effectively enhances the first hyperpolarizability (beta(0)) but also changes the spin multiplicity of the systems, which is useful to designing the smaller nanoscale spin and optical device. Here, special shaped species with a singlet diradical or multiradical character exhibit a very large beta(0) value, up to 1.7 x 10(5) au. Interestingly, it is found that the large beta(0) value is not presented in the high-spin trapezoidal 3-1 ((3)A) and triangle 3-2 ((5)A), but in the low-spin 3-1 ((1)A) and 3-2 ((1)A), which are unusual cases.