In continuation of our research on new chromophores for photoinitiators (Pis) we investigated a series of double and triple bond containing Pis based on benzophenone (BP), thioxanthone, benzil (BZ), benzildimethylketal (BDK), and hydroxyalkylphenone. UV-Vis spectroscopy revealed an absorption shifted up to 50 nm to the visible range of the spectrum. With steady state photolysis experiments, the rates of decomposition (R-d) were determined. Compared to the commercially available reference Pis the Rd of the new Pis were nearly identical. By quenching reactions with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), alpha-cleavage was identified for Type I initiators. Generally, all new compounds are suitable as PI especially for longer wavelengths. Nevertheless it has to be noted that the PI concentration has to be selected carefully to achieve optimum reactivity. (C) 2007 Wiley Periodicals, Inc.