The absorption and emission properties of three thienyl ketones (phenyl 2-thienyl ketone, di-2-thienyl ketone, and cyclopenta[2,1-b:3,4-b’]dithiophen-7-one) were investigated in several solvents. By comparison of experimental results with CNDO/S calculations, the lowest electronic transitions were assigned. Triplet-triplet transient spectra, triplet lifetimes, and quantum yields were determined. For the first two molecules, very effective spin-orbit coupling was found, and phosphorescence was observed in both fluid solutions and frozen glasses. For the cyclic ketone the dominating deactivation process was internal conversion from the S-1 state to the ground state.