Organic–inorganic halide perovskites have demonstrated tremendous potential for next-generation electronic and optoelectronic devices due to their remarkable carrier dynamics. Current studies are mostly focused on polycrystals, since controlled growth of high-quality single crystals is challenging. In this presentation, I will discuss strategies that enabled the first chemical epitaxial growth of single-crystal hybrid halide perovskites. Using advanced microfabrication, homo-/hetero-epitaxy, and a low-temperature solution method, single crystals can be grown with controlled locations, morphologies, orientations, and strain levels. By a lifting off approach, single-crystal thin films can be transferred from the epitaxial substrate to a general flexible substrate. Extending this strategy to low-dimensional perovskites yields nanostructured superlattices, based on which a solar cell with an open-circuit voltage exceeding the Shockley-Queisser limit is demonstrated. This approach opens up broad opportunities for hybrid halide perovskite materials based flexible high-performance electronic and optoelectronic devices.