An aqueous organic pigment dispersion contains a green copper phthalocyanine pigment and an azo-coupled -ketoamide pigment. It also includes an organic pigment dispersant at 40 weight % to 100 weight %, based on the sum of the weights of the organic pigments. The weight ratio of the green copper phthalocyanine pigment to the azo-coupled -ketoamide pigment is from 1:1 to 10:1. The median particle diameter of each of the green copper phthalocyanine pigment and the azo-coupled -ketoamide pigment is less than 85 nm. At least 95% of the total particles of each of the green copper phthalocyanine pigment and the azo-coupled -ketoamide pigment have a particle diameter of less than 150 nm. This dispersion can be used to prepare aqueous green inkjet ink compositions that can be used in various inkjet printing methods.

An organic thin film transistor containing a compound represented by one of the following formulae in a semiconductor active layer has a high carrier mobility and a small change in the threshold voltage after repeated driving. X represents S or O, and at least one of R.sup.1 to R.sup.6 represents -L-R wherein L represents alkylene, etc., and R represents alkyl, etc. ##STR00001##