Avian infectious bronchitis virus (IBV) is a globally prevalent, highly contagious avian pathogen that imposes substantial disease burden and economic losses on the poultry industry. Due to the challenges associated with vaccine immunization, there is an urgent need to develop novel anti-IBV therapeutic strategies. In this study, a synthesized novel compound N-phenethylphenazine-1-carboxamide (SQXA-12) was investigated for its significant inhibitory effects on IBV replication. SQXA-12 exhibited low cytotoxicity and high antiviral efficacy, with a CC50 value of 122.98 μM and an EC50 value of 12.25 μM. Sensitivity tests against VSV, HCoV-OC43, PEDV, NDV, PRRSV, and AIV-H9N2 revealed that SQXA-12 possesses potential broad-spectrum antiviral activity against both positive- and negative-sense RNA viruses. These findings highlight the promising therapeutic potential of SQXA-12 for IBV infection.