Gemini surfactants, double sodium alpha-sulfonic polyethylene glycol laurate (abbreviated C-12-PEG-C-12), were prepared and applied as soft templates in the controlled synthesis of BaCrO4 and PbCrO4 micro/nanocrystals. The template effects were investigated by adjusting the length of the spacer, using PEG400 and PEG4000, of the Gemini surfactant. The results indicated that the size and morphology of BaCrO4 and PbCrO4 micro/nanocrystals varied with the change in spacer length of C-12-PEG-C-12, suggesting that the different lengths of the polyethylene glycol group spacers in the Gemini surfactants played a key role in determining the size and shape of the MCrO4 micro/nanoparticles. The dynamic process of the formation of the novel morphology BaCrO4 crystals showed that the morphology grew from a round-bar polyhedron, to regular polyhedron, to approximate octahedron to a uniform pistachio nut shape. The growth mechanism of the BaCrO4 micro/nanocrystals was explained that C-12-PEG-C-12 had a greater interfacial adsorption and would effectively control the shape evolution during the crystal growth, while PbCrO4 could be explained that the Gemini surfactants can undergo liquid-crystalline phase transitions with long channels providing a soft template effect and derived the nanorods formation. Room temperature fluorescence spectra were studied and these showed that the pistachio-shaped BaCrO4 microcrystals and PbCrO4 nanorods possess photoactive luminescence properties with emission peaks at 470 and 549 nm, respectively. (C) 2010 Elsevier B. V. All rights reserved.