Hexagonal GdBO3:Eu3+ with different morphologies, such as nanofibres, microspheres, microflowers and novel lotus leaf-like microstructures, have been successfully synthesized by complexing-agent-assisted hydrothermal process for the first time. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected-area electron diffraction (SAED), energy-dispersive spectra (EDS), and photoluminescence (PL) spectroscopy were employed to characterize the as-obtained products. It was found that the reaction temperature and the pH value have crucial influences on the formation and morphology of the resulting structures and morphologies. The possible formation mechanisms for different structures were put forward. A detailed investigation on the photoluminescence of GdBO3:Eu3+ different samples indicate that the luminescence properties of as-obtained GdBO3:Eu3+ phosphors are strongly dependent on the morphology, size and crystallinity. The microflower structure exhibits the strongest red emission. (C) 2011 Elsevier B.V. All rights reserved.