The possibility to excite directly at 185 nm chromophores that absorb in the vacuum-UV has stimulated increased activity during the last decade in this field of photochemistry. Whereas photochemical reactions a t L < 200 nm have been thoroughly investigated in the gas phase, only recently have intensive studies on the 185-nm photochemistry of organic compounds in solution provided new insights. Despite the high excitation energies, selective photoreactions are promoted in the short-lived singlet excited states (Rydberg photochemistry). In contrast to conventional photochemistry (A > 220 nm), 185-nm irradiation preferentially results in intramolecular rearrangement, fragmentation, and isomerization reactions. Intermolecular radical couplings and abstractions as well as dimerizations (n,x*-excitation) com-Pete minimally. Besides the straightforward denitrogenation of photoresistant ("reluctant") azoalkanes, important applications of the short-wavelength photolysis are also found in technology (photolithography) and medicine (193-nm laser). Broadening the scope of the synthetic potential of the 185-nm photochemistry, which so far has been limited to direct cis/trans isomerizations, presents a challenge for the chemist.