Abstract Water-soluble anthracene derivatives containing carboxy, dihydroxyphosphinyl, or pyridinium fragments bound via methylene groups to 9-and 10-carbon atoms were prepared, and their spectra, solubility, and reactivity toward singlet oxygen were studied. Using sodium α, α'-(anthracene-9, 10-diyl) bis (methyl-malonate) as acceptor, it is possible to determine the quantum efficiency of singlet oxygen generation in aqueous solutions ...