A triphenylene-based conjugated microporous polymer (TP-CMP) has been synthesized and shows high surface area (S_BET = 1104 m² g⁻¹) and remarkable uptakes of H₂ (7.08 mmol g⁻¹ at 77 K and 900 mmHg) and CO₂ (3.37 mmol g⁻¹ at 273 K and 900 mmHg). In addition, it could be utilized to detect nitrobenzene selectively via fluorescence quenching.