Diagonal corner-to-corner sub-resolution assist features for use in photolithography are described. The diagonal features may be applied to one or a group of main features. Such features may be developed starting by synthesizing a photolithography mask having a first feature aligned along a linear axis and having a corner and a second feature aligned along a linear axis and having a corner, the corners of first and second features being separated from each other by a gap. The features may be developed by determining at least one diagonal line between the corners of the features to bridge the gap between the corners, applying a sub-resolution assist feature along the determined line, and modifying the synthesized photolithography mask to include the sub-resolution assist feature.