One-dimensional (1D) semiconductor nanostructures are of prime interest due to their potentials in investigating the size and dimensionality dependence of the materials’ physical properties and constructing nanoscale electronic and optoelectronic devices. Recent advances in the design and control of heterostructures and superlattices in 1D nanoscale semiconductors have opened the door to new device concepts. 1D heterostructures consisting of two or more important functional materials are of prime importance for revealing unique properties and essential for developing potential nanoelectronic and optoelectronic devices. On the other hand, the controlled growth of twinned superlattices within a single nanostructure could facilitate bandgap engineering and reveal novel electronic behaviours. In addition, an attractive challenge is to achieve the entire growth control within an individual nanostructure, e.g. to make highly reproducible, periodically twinned superlattices with an adjustable twin spacing. This Highlight article reviews some recent key advances in the field and outlines potential future areas that require immediate research and development.