1 A Molecule-Based 1:2 Digital Demultiplexer Joakim Andréasson, *,† Stephen D. Straight, ‡ Subhajit Bandyopadhyay, § Reginald H. Mitchell, § Thomas A. Moore, *,‡ Ana L. Moore, *,‡ and Devens Gust *,‡ Department of Chemical and Biological Engineering, Chalmers University of Technology, SE-412 96 Göteborg, Sweden, Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604, USA, and Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC, Canada V8W 3V6 RECEIVED DATE (to be automatically inserted after your manuscript is accepted if required according to the journal that you are submitting your paper to) A trichromophoric molecule consisting of a porphyrin linked to both a dihydropyrene and a dihydroindolizine-type photochrome, in combination with a third harmonic generating crystal, functions as a 1:2 digital demultiplexer with photonic inputs and outputs. Each of the two photochromes may be cycled independently between two metastable forms, leading to four photoisomers, three of which are used in the demultiplexer. These isomers interact photochemically with the porphyrin in order to yield the demultiplexer function. With the address input (1064 nm light) off, one output of the device (porphyrin fluorescence) tracks the state of the data input (532 nm light). When the address input is turned on, the second output (absorbance at 572 nm) tracks the * Corresponding authors. E-mail a-son@chalmers.se (JA), gust@asu.edu (DG), tmoore@asu.edu (TAM), amoore@asu.edu (ALM.) † Chalmers University of Technology ‡ Arizona State University § University of Victoria