A soluble polyaniline (PANi) was synthesized by modifying with a photolabile, acid-labile, and thermolabile tert-butoxycarbonyl (t-BOC) group in this study. The prepared PANi(t-BOC) is highly soluble and thermodynamically stable in low-boiling solvents such as THF, dioxane, and CHCl3. This soluble form of PANi(t-BOC) was converted to the insoluble and electrically conductive emeraldine salts upon photodoping with only a catalytic amount of photoacid generators such as N-(tosyloxy)- or (camphorsulfonyloxy)norborneneimide or -onium salts. As a result of this solubility difference, conducting patterns of high resolution were produced by conventional photolithography process. Further, upon removal of the t-BOC groups in PANi(t-BOC) by acid doping, no obvious morphology change of the films was observed, and such conversion recovered the original conductivity level of the doped PANi. Since the t-BOC protecting groups are easily removed in doping or acid-catalyzed reaction by chemical amplification or thermal bake, the PANi(t-BOC) can be used as conductive matrix polymers for negative type photoimaging or printing materials or for novel solution-processed applications in various microelectronic devices.