Disclosed are a series of photoisomeric compounds, preparation method therefor and device comprising the compounds, wherein a photoisomeric compound-graphene molecular junction device is formed by linking the photoisomeric compound to a gap of two-dimensional monolayer graphene having a nano-gap array via an amide covalent bond. When a single photoisomeric compound is bridged to the gap of the two-dimensional monolayer graphene having a nano-gap array, the devices have a reversible light-controlled switching function and a reversible electrically-controlled switching function. A molecular switch device prepared by the method can achieve a high reversibility and a good reproducibility. The number of light-controlled switching cycles can exceed 104, and the number of electrically-controlled switching cycles can reach about 105 or greater. Moreover, the above-mentioned reversible molecular switch device remains stable within a period of more than one year. In addition, flexible non-losable organic memory transistor devices and light-responsive organic transistor devices can be constructed using the above-mentioned series of photoisomeric compounds.