Substituted graphenes without centrosymmetry can be considered as a new acceptor-graphene model for NLO materials and exhibit large static first hyperpolarizabilities (beta(0)). Especially, three interesting relationships between the defect structure and beta(0) value are observed. We found that the defects (for example, the Stone-Wales and 585 defects) in graphenes can greatly enhance beta(0) values up to 1.4 x 10(5) au (about 1200 x 10(-30) esu), which shows that the defect is a new factor for enhancing beta(0) value. Meanwhile, large HOMO-LUMO gaps (4.595-5.982 eV) and vertical ionization potential values (8.059-13.572 eV) indicate that those substituted graphenes molecules have chemical stabilities. (C) 2011 Elsevier B.V. All rights reserved.