With the support of the Chemical Mechanism, Function, and Properties Program of the Division of Chemistry, Professor Dennis Cao of the Chemistry Department at Macalester College is developing a class of organic dye compounds that interact with near-infrared light. The goal of this research is to unlock design principles toward organic dyes that can harvest solar energy outside the visible region of light and/or serve as imaging agents deep within living tissue. The research activities in synthesis and photophysical characterization will be conducted by undergraduate researchers both in laboratory courses and in full-time summer positions, providing excellent training and workforce development. The Cao Lab will also host visiting graduate student researchers and provide them with first-hand experience of running a research program and mentoring in the context of an undergraduate institution. Computational investigations suggest that the pyrazoloindazole scaffold has remarkable potential as a near-infrared (NIR) chromophore, with an electronic structure that is 1) sensitive to structural modifications for varying the HOMO-LUMO gap and 2) likely to be a NIR light emitter. Curated libraries of modified pyrazoloindazoles will be synthesized and investigated to identify design rules for achieving compounds with enhanced absorption and/or emission maxima longer than 700 nm. The project team additionally will investigate the redox activity of the pyrazoloindazole scaffold in antic