The synthesis of 1,4-benzoquinones carrying, severally, the side-chains [CH2]2·OH, CH2·CH(OH)Me, [CH2]2·Ph, CH2·CHPh2, [CH2]2·CO2Et, CH2·CH(CO2Et)2, cis- and trans-CHCHPh, CHCPh2, and CO·CHCHPh is described. When irradiated with visible light the hydroxyalkylquinones yield the corresponding carbonyl compounds. The phenyl-, diphenyl-, and ethoxycarbonyl-ethylquinones and the β-phenylstyrylquinone give 2,3-dihydrobenzofurans. Mechanisms are discussed. Diethyl (1,4-benzoquinonyl)methylmalonate is essentially unchanged. The remaining quinones afford unidentified amorphous products.