A new heterocyclic azodye 4-({4-[(7-Chloroquinolin-4-yl)amino]phenyl}diazenyl)naphthalen-1-ol (CQAPDN) was synthesized by diazotization of 7-chloroquinolin-4-yl)benzene-1,4-diamine; followed by coupling with α-naphthol. Its structure was elucidated by spectroscopic techniques. Dyeing performance on polyester fibers was assessed. The color strength measurements and fastness properties exhibited good results. The electrochemical behavior of the CQAPDN was studied using cyclic voltammetry technique in a mixed solvent of perchloric acid and acetonitrile at glassy carbon electrode modified with poly1,5-diaminonaphthalene. The modified electrode showed excellent electrocatalytic activity toward electrochemical determination of CQAPDN with low detection and quantification limits of 0.00169 and 0.00565 µM. The azo-removal was studied using controlled potential electrolysis technique at 0.20 V. The decolorization efficiency was assessed through UV/Vis studies confirming that the azo-group was destroyed.