Triblock blue/orange and multiblock blue/green organic microtubes are prepared via a liquid-phase co-assembly method by Y. S. Zhao, J. N. Yao, and co-workers on page 1703. In this image, the controllable doping of orange/ green acceptors in the blue-emitting matrix is compared to optional painting with a brush in different colors. The fluorescence image in the background shows the well-defined morphology and high monodispersity of the samples. These light-emitting heterostructures are applicable for integrated microscale optoelectronics as functional wavelength converters.