In this paper the bi-molecular interactions of some heteroaromatic (thienyl phenyl, dithienyl, and thienyl pyridyl) ketones with isobutanol were studied by using nanosecond laser flash photolysis in trifluoroethanol at room temperature. The absorption spectra of the triplets and ketyl radicals and their decay dynamics were investigated. Depending on the thienyl ring position (2 or 3), two types of photobehavior were found: (1) the 2-thienyl ketones, which have lowest triplets of pi,pi* character, abstract hydrogen at a slow rate (k(H) < 2 x 10(4) dm(3) mol(-1) s(-1)) and (2) the 3-thienyl ketones, which have lowest triplets of n,pi* character, abstract hydrogen at a faster rate (k(H) similar to 3 X 10(5) dm(3) mol(-1) s(-1)). For most of the latter compounds, both n,pi* and pi,pi* triplets are spectrally and kinetically observed. While in 2-thienyl ketones the upper reactive n,pi* triplet is thermally populated by the lowest pi,pi* one, in 3-thienyl ketones the two states are independent populated from the singlet state and vibronic mixing between them is not efficient.