The invention pertains to a photo-sensitive composition which comprises a photochemical initiator, a polyacid or a salt thereof, and a poly(3,4-alkylenedioxythiophene) wherein the alkylene moiety is —(CH2)n-, n being an integer from 1 to 3, or 1,2-cyclo-hexylene, which may optionally be substituted, characterized in that the photochemical initiator is a water-soluble polymer comprising at least two azide or diazonium groups. Preferably, the water-soluble polymer is chemically stable at pH 6 or less, more preferably at pH 2 or less.