The polarizability(a)and second hyperpolarizability(γ)were systemically investigated for singlet diradical complex involving X(X=B,Al,Ga)atom.The results show that both the a and γ can be effectively tuned by varying the distance R(between compound A and a water molecule)and acceptor atom X.The lone pair of electrons from the O atom of the water molecule entered into the vacant p orbital of atom X,which increased the diradical character and led to the increase of the a and γ values.Furthermore,the polarizable continuum model(PCM)was used to test the effects of H2O and CCl4 solvents on the α and γ values.Both the a and y values of the studied diradical complex 1a(1b,1c)in H2O and CCl4 were uniformly enhanced.And the solvent effects of H2O on either a or γ were larger than those of CCl4.