In this work, a novel quasi-photonic crystal fiber has been proposed, for the first time, in the chemical sensing purpose in the terahertz (THz) regime. Along with the sensing response, power fraction, scattering loss, effective mode area, and V parameter have been numerically computed by the full-vector finite element method with anisotropic circular perfect matched layers. Numerically computed results show that the proposed sensor offers 70.94%, 71.06%, and 72.19% sensing responses for targeted analytes water, ethanol, and benzene respectively at the optical frequency f = 1 THz. Besides, effective mode area of 1.43 × 10⁵ µm², 1.48 × 10⁵ µm² and 1.55 × 10⁵ µm² have found at the same time for the same analytes. The Q-PCF model proposed in this paper have bright aspects for practical applications in clinical and diagnostic sensing, medical imaging, environmental monitoring purpose and many other fields related to it.