While photochemical synthesis offers access to spatiotemporal reaction control, its potential to selectively address specific reactions by the colour of light is usually limited by ubiquitous spectral absorption overlaps of the reactive groups.H erein, an ew concept is introduced that actively suppresses one ligation reaction by triggering the cycloreversion of the [2+ +2] cycloaddition of styrylpyrene. Combination of the photoreversible styrylpyrene chemistry with the [4+ +4] cycloaddition of 9-triazolylanthracene makes it possible to initially induce chain coupling using UV light and to subsequently ligate the formed single-chain nanoparticle (SCNP) with asecond polymer chain using blue light. Seizing upon the first sequence-independent l-orthogonal reactivity established here,t he same macromolecular architecture was obtained in reverse irradiation sequence,b yb lue and subsequent violet light irradiation-completely foregoing highenergy UV light.