Molecular orientation and packing structure of small molecular organic semiconductors are very important for the charge carrier mobility of organic thin-film transistors (OTFT). Furthermore, the miscibility of p-and n-type materials and the grain size of each material in bulk heterojunction are critical for the performance of organic photovoltaics (OPVs). Benzoporphyrins (BPs) are one of the outstanding p-type organic semiconductors and have been studied for OTFT and OPV materials [1]. For practical use of organic electronic devices, solution process is desirable but BPs are not soluble in organic solvents.To achieve the solution process of BPs, two strategies have been studied in the last two decades. One is a precursor approach: as-spun films of soluble precursors of BPs are in-situ converted into BP thin-films by retro-Diels–Alder reaction. With this method, the film of intact BP is available but the mixed film of edge-on and face-on grains are obtained because of the too-good crystallinity of BPs. The other is a substituent engineering: proper substituents induced to the BP framework can improve the solubility and processability of the film as well as the morphology and orientation of the molecules. Recently we were successful to obtain edge-on dominant film of BP derivatives by a simple dip-coating. 5,15-triisopropylsilyl-ethynyl(TIPS)-BP could make brickwork-type packing to achieve 1.1 cm2 V-1 s-1 FET charge carrier mobility (m FET) [2].This side-chain engineering was also effective for the control of packing structure of bulk-hetero junction OPV. The alkyl chain length drastically influenced the miscibility of p- and n-materials and the short-circuit current density [3]. We also found open-circuit-voltage shift of over 0.5 V in organic photovoltaic cells induced by a minor structural difference in alkyl substituents of acene-type p-materials [4]. In this presentation, the relation between control of packing structure and the OPV performance will be discussed.