Abstract: The highly efficient and simple approach for the preparation of poly-substituted quinolines derivatives through Friedlander hetero-annulation reaction and Pfitzinger condensation reaction between 2-aminoaryl ketones or isatin and active methylene carbonyl compound of cyanoacetyl indole in the presence of p‑toluenesulphonic acid (p-TSA) catalyst was reported. The molecular structure of 3-cyano-2-indolyl quinoline derivatives synthesized in the present work, namely 6-chloro-2-(1H-indol-3-yl)-4-phenyl-quinoline-3-carbonitrile (Q-1), 2-(1H-indol-3-yl)-6-nitro-4-phenyl-quinoline-3-carbonitrile(Q-2), and 3-cyano-2-(1H-indol-3-yl)-quinoline-4-carboxylic acid (Q-3) were confirmed by 1H-NMR, mass and FTIR spectroscopic analyses. Further, the title compounds electrochemical band gap value was found to be 2.4, 2.22, and 2.7 eV for the compounds Q-1, Q-2, and Q-3 respectively and their corresponding emissive quantum yield were 0.66, 0.65, and 0.34, respectively.