Bottom-up assembly of monodisperse microfluidic droplets is an established route to engineer ordered structures with a periodicity of tens to hundreds of microns. When the microfluidic droplets are oil-in-water-in-oil (o/w/o) double emulsions, inverse opals with enclosed voids are derived by initiating the crosslinking within the shells and across the emulsion interfaces, accompanied by the gradual evaporation of the cores. The morphology and periodicity of the inverse opals are tailored by the emulsion size, the shell thickness, and the sol-gel transition and evaporation dynamics, etc. (C) 2018 Elsevier Ltd. All rights reserved.