The α ( 4 He) -clustering structure is a common phenomenon in light nuclei due to the decreasing contribution of mean field in few-body system. In this work we presented calculations of giant dipole resonance (GDR) excitations for two non α-conjugate light nuclei, namely 6 Li and 9 Be, within a framework of an extended quantum molecular dynamics model. For 6 Li, we investigated the GDR spectra from the two-body clustering structure with α + deuteron as well as the threebody structure with α + n + p, and found that the major α-clustering contribution on the GDR peak is located at around 31 MeV, while the resonance contributions between clusters, namely α and deuteron or (n + p), are located on the lower energy side, which can be regarded as pygmy dipole resonance (PDR). For 9 Be, a mixture configuration contribution for the Chain-like structure and Borromean-like structure of the α + n + α configuration can somehow explain its GDR results.