Subtle engineering for the generation of a biosensor from a conjugated polymer with the inclusion of fluorine-substituted benzothiadiazole and indole moieties is reported. The engineering includes the electrochemical copolymerization of the indole-6-carboxylic acid (
M1
) and 5-fluoro-4,7-bis(4-hexylthiophen-2-yl)benzo[
c
][
1
,
2
,
5
]thiadiazole (
M2
) on the indium tin oxide and graphite electrode surfaces for the investigation of both their electrochemical properties and biosensing abilities with their copolymer counterparts. The intermediates and final conjugated polymers, Poly(M1)
[P-In6C]
, Poly(M2)
[P-FBTz]
, and copoly(M1 and M2)
[P-In6CFBTz]
, were entirely characterized by
1
H NMR,
13
C NMR, CV, UV-Vis-NIR spectrophotometry, and SEM techniques. HOMO energy levels of electrochemically obtained polymers were calculated from the oxidation onsets in anodic scans as −4.78 eV, −5.23 eV, and −4.89 eV, and optical bandgap (Eg
op
) values were calculated from the onset of the lowest-energy π–π* transitions as 2.26 eV, 1.43 eV, and 1.59 eV for
P-In6C
,
P-FBTz
, and
P-In6CFBTz
, respectively. By incorporation of fluorine-substituted benzothiadiazole (
M2
) into the polymer backbone by electrochemical copolymerization, the poor electrochemical properties of
P-In6C
were remarkably improved. The polymer
P-In6CFBTz
demonstrated striking electrochemical properties such as a lower optical band gap, red-shifted absorption, multielectrochromic behavior, a lower switching time, and higher optical contrast. Overall, the newly developed copolymer, which combined the features of each monomer, showed superior electrochemical properties and was tested as a glucose-sensing framework, offering a low detection limit (0.011 mM) and a wide linear range (0.05–0.75 mM) with high sensitivity (44.056 μA mM
−
1
cm
−
2
).