Photochemical oxidation of acenes can benefit or impedet heir function, depending on the application.A lthougha cenes with alkoxy substituents on reactive sites are important for applications as diverseasdrug delivery and organic optoelectronics, the influence of chemical structure on their photochemical oxidation remainsu nknown. This paper therefore describes the synthesis, spectroscopic properties, and reactivity with singlet oxygen ( 1 O 2 )o faseries of dialkoxyacenest hat varyi nt he number and types of fused rings in the (hetero)acene cores. Reductive alkylationofquinone precursorsy ieldedt arget dialkoxyacenesw ith fused backbones rangingf rom benzodithiophene to tetracenothiophene. Trends of their experimental spectroscopicc haracteristics were consistent with time-dependent density functional theory( TD-DFT) calculations.N MR studies show that photochemically generated 1 O 2 oxidizes all but one of these acenest ot he corresponding endoperoxidesi no rganic solvent. The rates of these oxidations correlate with the number and types of fused arenes,w ith longer dialkoxyacenesg enerally oxidizing faster than shorterd erivatives. Finally,i rradiation of these acenes in acidic, oxidizing environmentsc leavest he ether bonds. This work impacts those workingi no rganic optoelectronics, as well as those interested in harnessing photogenerated reactive oxygen speciesi n functional materials.[a] Dr.