This experimentation study examined the performance and emission characteristics of a stock single-cylinder engine with changing compression ratios by blending different quantities of safflower seed oil (SFSO 05, SFSO 10, SFSO 15, SFSO 20, SFSO 25, and SFSO 30) with diesel fuel. The engine has been subjected to evaluation and discharge gas emissions tests as well as obtained performance comparison and exhaust gas emission measures including brake precise fuel consumption (BSFC), brake power (BP), thermal efficiency (BTE), brake carbon monoxide (CO), hydrocarbons (HC), and Nitrogen Oxide (NOx) under various loading conditions (0, 20, 40, 60, 80 a). The experimental research output results show that combining diesel fuel and safflower seed oil significantly improves the quality characteristics of test engines. In comparative analysis with pure diesel fuel, some emission characteristics are also observed better than pure diesel fuel. SFSO30 blends outperform six different safflower seed oil blends in relation to engine performance and emission parameters. © 2024 Elsevier B.V., All rights reserved.