<p>A novel thieno[3,2-b]thiophene (TT) was utilized for the first time to electrochemically fabricate an ionic liquid (IL)-supported polythieno[3,2-b]thiophene (PTT) coating. This innovative coating serves as a new headspace solid-phase microextraction (HS-SPME) material for the extraction of five phenolic compounds, which were subsequently determined via gas chromatography-mass spectrometry (GC–MS). The coating was characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Experimental results confirmed that the ILs were successfully embedded within the polymer matrix, resulting in a well-defined three-dimensional mesoporous architecture. This unique architecture not only exhibited high thermal stability but also maintained a consistent extraction performance when used for the solid-phase microextraction of phenolic compounds. To optimize the extraction and detection performance, various experimental parameters were investigated, including the coating type, pH, salt concentration, extraction time, extraction temperature, stirring rate, desorption time, and temperature. Under the optimal conditions identified, the method exhibited low limits of detection ranging from 0.001 to 0.007 μg mL⁻¹ and wide linearity in the concentration range 0.030 to 10.000 μg mL⁻¹. Noteworthily, the proposed method was successfully applied to the determination of five phenols in actual water samples, achieving satisfactory recoveries between 90.5% and 110.5%‌.</p> Graphical Abstract <p></p>