Abstract: Morpholinos are widely used to block the activity of selected single-stranded genetic sequences. This invention comprises Morpholinos containing one or more integral photolinkers (Photo-Morpholinos) wherein the photolinkers are directly incorporated into the sequence of a Morpholino, where the photolinker has a size and structure which emulates the size and structure of a Morpholino subunit. This integrated photolinker design substantially simplifies and reduces cost of production relative to earlier photocleavable compositions. The invention also comprises use of these Photo-Morpholinos for modulating the expression of any selected gene transcript at any selected time and at any selected site simply by exposure to light. These Photo-Morpholinos afford a new use wherein a gene transcript is rendered inactive by contacting with a Photo-Morpholino—and then later exposure to light cleaves the Photo-Morpholino to inactive fragments—thereby reactivating that previously inactivated gene transcript.