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[Display omitted] • A metal-free catalytic system is used for hydrogenation of coal pitch (CP). • Hydrogenated CP (HCP) is rich in aliphatic side chain and naphthenic structure. • Wide-area streamlined mesophase pitch with low softening point is prepared from HCP. Coal pitch (CP) molecules have high aromaticity, planarity and condensation degree, usually requiring hydrogenation to prepare high-quality mesophase pitch (MP). However, current hydrogenation methods often face challenges such as harsh conditions, residual ash or insufficient hydrogenation. Here, with 5 wt% tetrahydronaphthalene (THN) as the hydrogen donor, hydrogenated CP (HCP) with low ash content and high H/C was prepared at low temperature and pressure via a metal-free catalytic system with boron trifluoride ether (BF 3 ·Et 2 O) as catalyst and p-toluenesulfonic acid (TsOH) as co-catalyst and 5 wt%. Subsequently, MP was prepared from the HCP, and the mechanisms of catalytic hydrogenation and the formation of mesophase macromolecules were elucidated. The characterization results indicated that CP achieved optimal hydrogenation when the molar ratio of BF 3 to TsOH was 1:1. The HCP obtained under this condition can further prepare a wide-area streamlined MP. During the hydrogenation process, TsOH provided proton hydrogen to BF 3 , forming a complex acid that facilitated carbocation reactions between THN and CP molecules, thereby enhancing hydrogenation efficiency. However, when the molar amount of TsOH exceeded that of BF 3 , it would catalyze the polymerization of HCP molecules to a certain extent, reducing the hydrogenation effect. Meanwhile, it could introduce more sulfonic acid groups into the molecular structure, causing cross-linking of polycyclic aromatic hydrocarbons and excessive system viscosity during the preparation of the MP, resulting in a mosaic optical texture. This work is of significant importance for promoting the efficient hydrogenation of CP and the preparation of high-quality MP. [ABSTRACT FROM AUTHOR]