An organic thin film transistor (“TFT”) array panel includes a substrate, a gate line extending in a first direction, a data line extending in a second direction, intersecting with and insulated from the gate line, a source electrode connected to the data line, a drain electrode facing the source electrode, a pixel electrode connected to the drain electrode, and an organic semiconductor connected to the source electrode and the drain electrode, the organic semiconductor made of an organic material with photosensitivity.