To better understand mechanisms of fluorescence modulation in ssDNA-SWCNT, we performed a structure-activity relationship study on a class of sensors for catechol (benzene-1,2-diol)-bearing small molecules. Previous studies have shown that (GT)N-SWCNT (N = 6-15) conjugates undergo a strong fluorescence turn-on in response to catecholamines, with reported affinities in the nanomolar to single micromolar range. These sensors have enabled significant advancement in the field of catecholamine biology, including dopamine (4-(2-aminoethyl) benezene-1,2-diol), in cell cultures and tissues . Nanotube-based catecholamine sensors are notable for their robustness, intensiometric readout, high signal-to-noise ratio, and rapid, and reversible responsesattributes highly valued in biological applications. We propose that this class of sensors can serve as a model system from which mechanistic insights benefitting the broader field may emerge. By focusing on these well-characterized systems, we aim to elucidate the fundamental principles governing the interaction between ssDNA functionalized SWCNTs and their analytes, potentially paving the way for the rational design of new biosensors.