The increasing global demand for energy production, storage, and handling has sparked great interest among researchers in thermoelectric (TE) materials, where heat sources like fossil fuel combustion, sunlight, and byproducts of industrial processes can be used for direct conversion between heat and electricity. The TE performance of a material is determined by the material’s dimensionless figure of merit, ZT, which is defined by α²σT/κ, where α is the Seebeck coefficient, σ is the electrical conductivity, κ is the total thermal conductivity, and T is the absolute temperature. A TE material should have high electrical conductivity and Seebeck coefficient, whereas low thermal conductivity for a maximised ZT value. Since electrical and thermal conductivities are inversely related, maximising the ZT value is a somewhat difficult achievement. It was observed in this study that producing a conductive path by a segregated network structure of TiB₂ overcame this phenomenon by creating different mean free path lengths for electrical carriers and phonons, simultaneously increasing electrical conductivity and decreasing thermal conductivity, resulting in an improved ZT value for boron carbide (B₄C). Polycrystalline bulk samples of B₄C with segregated network structures of in-situ TiB₂ were prepared by the spark plasma sintering (SPS) method starting from TiC-coated B₄C granules. TiB₂ was chosen as a network material for its high electrical conductivity. Phase and microstructure analyses were carried out on polished surfaces of the sintered bulk samples. An X-ray diffractometer (XRD) was used to determine phase purity, possible reactions between powders, and crystal structure. Microstructures were investigated by backscatter electron imaging (BSE) in SEM. The electrical conductivity and Seebeck coefficient values of the samples were measured from rod-shaped samples cut from sintered samples simultaneously by a thermoelectric analyser utilising the four-point probe method (FPP). Thermal diffusivity values were measured by a laser flash apparatus (LFA), whereas CP values were measured by differential scanning calorimetry (DSC) from ground powder samples between 323-923 K. Finally, density values were obtained by the Archimedes method at room temperature, and thermal conductivities of the samples were calculated. In-situ TiB₂ was formed as a result of a reaction between B₄C matrix particles and TiC coating particles. The Conductive in-situ TiB₂ segregated network structures increased the electrical conductivity of B₄C simultaneously with decreasing thermal conductivity by increasing phonon scattering due to the increased grain boundary density and porosities. Optimising initial TiC addition, thus TiB₂ volume fraction in the final structure, proved essential in limiting the decrease of the Seebeck coefficient. A maximum ZT value of 8.02x10^-2 was obtained with 1.5 vol. %. TiC addition, increasing the ZT of monolithic B₄C by an impressive ≈ 120 %. Limiting the secondary phase content thanks to the lower percolation threshold of the segregated network structures proved efficient in improving the thermoelectric performance and being cost-effective.