This paper proposes multi-band bandstop filters (BSFs) based on mixed electric and magnetic coupling resonators. The proposed structures include a multimode resonator based on symmetrical open-circuit branches, including upper- and lower-branch filter circuits. These filters allow for flexible and autonomous adjustment of stopband center frequencies. The filters exhibit excellent characteristics such as compact dimensions and abrupt roll-off skirts. Tri-band to sext-band BSFs were fabricated, and the measured results closely matched the simulated ones. The proposed structures are applicable in communication, information, and coal automation fields. The design process involves using open-branch multimode resonators to achieve compact structures with high stopband attenuation. The tri-band BSF design includes coupling branches and transmission branches, with the stopband center frequencies adjustable by modifying branch lengths and coupling spacing. The filters were modeled and simulated using 3D electromagnetic software, and the results were verified through fabrication and measurement. The tri-band BSF has stopband center frequencies of 1.91 GHz, 3.59 GHz, and 5.71 GHz, with 10 dB stopband bandwidths of 52.35%, 13.37%, and 10.52%, and corresponding attenuation values of 49.95 dB, 29.45 dB, and 44.71 dB. The quad-band BSF has center frequencies of 1.81 GHz, 3.41 GHz, 5.69 GHz, and 6.84 GHz, with bandwidths of 46.41%, 15.84%, 8.79%, and 11.11%, and attenuation values of 52.64 dB, 33.72 dB, 46.37 dB, and 49.73 dB. The quint-band BSF has center frequencies of 1.83 GHz, 2.52 GHz, 3.50 GHz, 4.19 GHz, and 5.72 GHz, with bandwidths of 21.86%, 31.87%, 9.71%, 17.90%, and 7.52%, and attenuation values of 45.06 dB, 43.91 dB, 24.53 dB, 32.86 dB, and 34.75 dB. The sext-band BSF has center frequencies of 1.83 GHz, 2.43 GHz, 3.59 GHz, 4.12 GHz, 5.19 GHz, and 5.77 GHz, with bandwidths of 21.82%, 32.92%, 8.91%, and 1This paper proposes multi-band bandstop filters (BSFs) based on mixed electric and magnetic coupling resonators. The proposed structures include a multimode resonator based on symmetrical open-circuit branches, including upper- and lower-branch filter circuits. These filters allow for flexible and autonomous adjustment of stopband center frequencies. The filters exhibit excellent characteristics such as compact dimensions and abrupt roll-off skirts. Tri-band to sext-band BSFs were fabricated, and the measured results closely matched the simulated ones. The proposed structures are applicable in communication, information, and coal automation fields. The design process involves using open-branch multimode resonators to achieve compact structures with high stopband attenuation. The tri-band BSF design includes coupling branches and transmission branches, with the stopband center frequencies adjustable by modifying branch lengths and coupling spacing. The filters were modeled and simulated using 3D electromagnetic software, and the results were verified through fabrication and measurement. The tri-band BSF has stopband center frequencies of 1.91 GHz, 3.59 GHz, and 5.71 GHz, with 10 dB stopband bandwidths of 52.35%, 13.37%, and 10.52%, and corresponding attenuation values of 49.95 dB, 29.45 dB, and 44.71 dB. The quad-band BSF has center frequencies of 1.81 GHz, 3.41 GHz, 5.69 GHz, and 6.84 GHz, with bandwidths of 46.41%, 15.84%, 8.79%, and 11.11%, and attenuation values of 52.64 dB, 33.72 dB, 46.37 dB, and 49.73 dB. The quint-band BSF has center frequencies of 1.83 GHz, 2.52 GHz, 3.50 GHz, 4.19 GHz, and 5.72 GHz, with bandwidths of 21.86%, 31.87%, 9.71%, 17.90%, and 7.52%, and attenuation values of 45.06 dB, 43.91 dB, 24.53 dB, 32.86 dB, and 34.75 dB. The sext-band BSF has center frequencies of 1.83 GHz, 2.43 GHz, 3.59 GHz, 4.12 GHz, 5.19 GHz, and 5.77 GHz, with bandwidths of 21.82%, 32.92%, 8.91%, and 1