Rinskor^TM active (Dow AgroSciences code number XDE-848; ISO name applied for but not yet obtained) is the trade name for a new herbicidal compound developed by Dow AgroSciences with intended use in rice and other crops. Structurally, Rinskor is a novel 6-arylpicolinate (6-AP) molecule consisting of a highly substituted 4-amino-pyridine ring (4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)-5-fluoro-pyridine-2-benzyl ester). Rinskor shares structural similarity with the recently introduced Dow AgroSciences herbicide: Arylex^TM active. Foliar application of Rinskor induces growth phenotypes similar to that of other auxin-like herbicides and growth regulators. Sensitive species exhibit rapid onset of auxinic symptoms that include wilting, epinasty, leaf malformation, tissue swelling, and stunted growth with necrosis. Plant death often occurs in days to several weeks after herbicide application. In order to analyze the physiological mode of action and site of action for Rinskor, whole plant studies on wild type and mutant Arabidopsis thaliana (ARBTH) were conducted in conjunction with surface plasmon resonance (SPR) molecule-protein interaction studies of the auxin binding proteins TIR1 and AFB5. Mutants harbored amino acid missense or nonsense changes in AFB5. Plants were either treated foliarly as rosettes prior to bolting or seeded in agar media supplemented with herbicide. In foliar applications of Rinskor, there was a 10-33 fold resistance of the AFB5 mutants over WT plants depending on the mutant line (based on 50% growth reduction (GR50) values of plant dry weight). WT and AFB5 mutants exhibited similar sensitivity to 2,4-D with GR50 values of 2.2 g ai ha^-1 and 2.7 – 9.9 g ai ha^-1 respectively. Phenotypic symptoms designate the mode of action of Rinskor as an auxin-like response. The susceptibility of AFB5 mutants to 2,4-D suggests that the molecular recognition site for Rinskor is not TIR1 but rather the AFB5 receptor. SPR analyses indicate a stronger affinity of Rinskor to AFB5 over TIR1. Whole plant mutant studies and protein specific interaction analysis indicate that Rinskor is an auxin herbicide with high affinity to the AFB5 protein.