This research article demonstrates a good simulation result for identifying and detecting various industrial chemicals in a Terahertz (THz) waveguide with a new heptagonal, five layers of heptagonal photonic fiber elliptic form, heptagonal cladding shape (H-PCF). COMSOL 4.2 software based on finite element (FEM) methods and perfectly matched layers check our composition (PML). The different chemicals are also differentiated and identified by each other in different parameters H-PCF fibers show a high relative sensitivity of ethanol of approximately 86.50 percent after numerical analysis, Benzene around 89.35%, and water around 85.15% at a frequency of around 0.7 THz. In our experiment, we obtained very low confinement losses at 1 terahertz (THz) such as 5.95 × 10⁻⁰⁸ dB/m for Ethanol 6.67 × 10⁻⁰⁸ dB/m for Benzene, and 5.80 × 10⁻⁰⁸ dB/m for water. Regarding these results, we can strongly recommend that our proposed heptagonal photonic crystal fiber (H-PCF) will be more congenial in biomedical, bio-medicine, and industrial areas for the identification and detection of various types of chemicals with the help of a THz waveguide.