resulting in device efficiencies exceeding 18%. [11] Applications for π-conjugated polymers requiring high conductivity are also being widely explored, most notably using highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) in fields such as energy storage, tissue engineering, and textile-based electronics. [12][13][14][15][16] Applying π-conjugated polymers in electronics requires the complimentary development of favorable optoelectrical and mechanical properties. Molecular orbital alignments and polymer crystallization are of paramount importance. These interactions impact numerous properties, such as the polymer band energies, [17] charge-transfer processes, [18] redox potentials, [19] and photophysics. [20,21] Close chain-packing facilitates interpolymer charge transport, improving charge mobility in polymers as charges move by a hopping mechanism. [22] Additionally, the nanoscale morphology has a strong impact on the efficiency of photophysical processes, including exciton diffusion and dissociation, which are vital for OPVs and OPCs. [23] For wearable electronics flexibility and stretchability must also be considered. The brittle nature of crystalline materials produced from π-conjugated polymers is one of the major challenges that remains to be solved. The highly crystalline ordering caused by strong noncovalent interactions, chain interdigitation, or rigid polymer backbones leads to high tensile moduli and low stress loadings. [24] Many approaches have been explored to overcome this challenge including copolymerizing or blending conjugated polymers with elastomers and forming gels. [25][26][27][28][29] Programmed assembly (Figure 1) is an emerging bridge between our understanding of morphological ordering and functional materials. Programming order means to intentionally control ordering and morphology through inputs to achieve a desired functionality. It is a tool for rational material design, enabling structural complexity via a bottom-up approach to combine and enhance desirable material properties. This complexity results from orthogonal chemistries, which can be activated sequentially to build up structures in a stepwise manner. By this approach, each function would be met with its appropriate structure, as a morphology is selected to in order to achieve well-defined properties.Herein, we provide a review of innovative efforts being explored to program order in π-conjugated polymers from the π-Conjugated polymers have numerous applications due to their advantageous optoelectronic and mechanical properties. These properties depend intrinsically on polymer ordering, including crystallinity, orientation, morphology, domain size, and π-π interactions. Programming, or deliberately controlling the composition and ordering of π-conjugated polymers by well-defined inputs, is a key facet in the development of organic electronics. Here, π-conjugated programming is described at each stage of material development, stressing the links between each programming mode. Covalent programming is performed during p...
