A photonic crystal fiber (PCF) made up of a spider-web such as cladding and an octagonal core is proposed for sensing applications. Three widely used industrial liquids and/or by-products, namely, water, acetic acid, and glycerol, have been investigated using the full vector finite element method. Extremely high sensitivities of 99.5%, 99.7%, and 99.9% were achieved at 4.5 THz for water, acetic acid, and glycerol, respectively. In addition to the sensitivity, extremely low effective material losses of 0.0004138, 0.000306, and 0.000113  cm^−  1 were achieved for water, acetic acid, and glycerol, respectively. Other parameters such as confinement loss, nonlinearity, and dispersion equally showed well-enhanced results compared to previous related works. The excellent sensing performance and ultralow confinement loss of this proposed PCF chemical-sensor make it a worthy candidate for use in many industrial sectors.