The development of a simple, template-free, and one-step strategy to synthesize nanostructured Au architectures with fascinating morphology is highly desirable and technically important due to their valuable applications in varied fields. In this work, the "green" strategy of "tunable ionic liquids-water (ILs-H2O) interfacial synthesis" developed previously by us is utilized for feasible synthesis of gold needle mushroom-like micro/nanostructures at the 1,3-dibutylimidazolium bis(trifluoromethylsulfonyl)imide ([C(4)bim][Tf2N]) - water interface and ambient conditions. The as-obtained gold needle mushrooms (AuNMs) have been characterized and analyzed systemically by scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. It is shown that the as-prepared AuNMs can be used as substrates to perform surface enhanced Raman scattering (SERS) investigation with striking SERS sensitivity. By employing ILs with different alkyl chain lengths of the imidazolium cations and/or different nature of anions, Au nanomaterials with diverse morphologies can be easily prepared at different ILs-H2O interfaces. Based on the analysis of the control experiments, the growth and formation of AuNMs at the [C(4)bim][Tf2N]-H2O interface have been discussed: (C) 2016 Elsevier Inc. All rights reserved.