Organic photodetectors with switchable photosensitivity are achieved using organic photoactive layers in electrode/organic/electrode structures. The photosensitivity can be switched on and off by the biasing voltage across the detectors, the switching voltage imparting photosensitivity above 1 mA/W at a preselected operating bias and near zero photosensitivity at a cut-off bias substantially equivalent in magnitude to the built-in potential of the photodetector. The photocurrent can be probled with a read-out circuit in the loop. These photodetectors can be arranged in linear arrays or in two-dimensional matrices that function as high performance, linear or two-dimensional image sensors.