In this work we describe the photoswitching properties of peri-anthracenethioindigo (PAT) and evidence its outstanding property profile as all-red-light responsive photoswitch. The PAT core structure was first synthesized more than 100 years ago by Paul Friedlaender as a potential chromophore 32 but has neither attracted much attention since nor has it ever been scrutinized for its photoreactivity to the best of our knowledge. Inspired by the performance of related peri-napththothioindigo photoswitches we set out to explore this unique molecular scaffold for its photochemistry. In the course of this work we have developed a straight forward and high yielding synthesis of PAT and appended the core structure with two mesitylene-groups to increase solubility in organic solvents. We found that PAT possesses outstanding photoswitching properties including absorptions up to 850 nm, pronounced negative photochromism with more than 140 nm maxima shift, good quantum yields for both switching directions, very high isomer accumulation in both switching states, and high thermal stability of the metastable Z isomer. Taken together with the rigid structure and double bond photoisomerization as the switching process, large and predictable molecular changes can thus be powered with very low energy light by direct excitation. Further, an application within a transparent polystyrene polymer and evidence of viable and spatially controlled NIRphotoisomerization with retained pronounced color contrast is delivered. We are thus expecting PAT to become a particularly valuable photoswitch tool for the full breadth of applications in all fields of chemical research.