Acenes are highly promising p-type organic semiconductors, and have been the subject of intense studies. However, acenes are often low in solubility and stability, which poses major obstacles in the synthesis and processing of this class of compounds. In order to overcome the problem, a series of α-diketone-type acene precursors have been developed. These precursors are generally more soluble and stable than the corresponding acene compounds, and their quantitative conversion can be achieved simply by photoirradiation both in solution and in the solid state. Further, the irreversible photoinduced removal of the -diketone unit can be used to alter the optoelectronic properties of fluorophores. This review overviews the synthesis and photochemical properties of α-diketone-type acene precursors, as well as their use as intermediates in preparation of large acenes or highly functionalized acene derivatives. Computational studies on the mechanism of α-diketone photolysis and the use of α-diketone derivatives in fabrication of organic devices are also summarized in this review.