We synthesized nanocomposite of polymerized 8-aminopyrene-1,3,6-trisulfonic acid (APTA) and single-walled carbon nanotubes (SWCNTs). To prepare the nanocomposite, SWCNTs were dispersed in aqueous solution of APTA (monomers) using a probe sonicator. The as-prepared APTA/SWCNTs dispersion was characterized using Raman, FT-IR, and UV-visible-near infrared (UVvis-NIR) spectroscopies. Cyclic voltammetrymeasurements indicated that polymerization of APTA occurred during probe sonication due to the oxidation of APTA molecules. Using the poly(APTA)/SWCNTs dispersion, a conducting thin film was prepared on a glassy carbon electrode (GCE) and its electrochemical and catalytic properties were studied. The poly(APTA)/SWCNTs film coated electrode exhibited excellent electrochemical catalytic activity toward the oxidation of caffeine (CAF) with a linear range from 10 mu M to 0.76 mM with a linear regression equation; Ipa (mA) = 0.015 mM + 5.84 x 10(-7) (R2 = 0.993). In addition, the other common electroactive biomolecules such as dopamine (DA) and ascorbic acid (AA) did not interfere with the CAF oxidation peak. Well-defined oxidation peaks (with high catalytic currents) ofAA(+ 0.49 V), DA(+ 0.53 V) and CAF (+ 1.47 V) were simultaneously observed at the poly(APTA)/SWCNTs sensor. Selective detection of CAF in fruit juices was also demonstrated. (C) 2016 The Electrochemical Society.