We synthesized complex 3D CdCO3 pyramids consisting of arrays of oriented CdCO3 parallel tetrahedrons using controlled seeded growth and Cd2+ cations that selectively adsorb onto CdCO3 basal planes as the structure-directing agent. A growth mechanism of 3D CdCO3 pyramids was suggested and explained in detail. The optical properties of some of these 3D CdCO3 pyramids were demonstrated by infrared (IR), UV-vis diffuse reflectance (UV-vis), and photoluminescence (PL) spectra, suggesting potential applications in electronic and optoelectronic devices. (c) 2012 Elsevier B.V. All rights reserved.