<p>Creation of bioreceptor layers with predetermined morphology and functionality on the surface of electrolyte-gated organic field-effect transistors (EGOFETs) is a challenge for researchers working on the development of liquid biosensors. In this work, a biotin-containing receptor layer was formed directly on the surface of organic semiconductor (component of an EGOFET device) using the azide-alkyne cycloaddition reaction proceeding by the click mechanism. A new alkyne-functionalized [1]benzothieno[3,2-<i>b</i>][1]-benzothiophene derivative allows one to carry out the Cu^I-catalyzed click reaction on the EGOFET surface. The effect of the content of the alkyne derivative in the organic semiconductor on the morphology and functionality of the resulting bioreceptor layer is assessed. Subsequent modification of the biotin fragments with streptavidin and a DNA aptamer as a selective receptor allowed one to create a biosensor that detects the influenza A virus at a concentration of 3 • 10⁶ virus particles mL⁻¹, which corresponds to the sensitivity of the antibody-based test strips.</p>