<p>The intense miniaturization and higher power density of contemporary electronic devices necessitate effective thermal management technologies to ensure reliable operation and prevent premature failure. Traditional cooling methods often fail to remove localized hot spots, making passive approaches, such as fin-based natural convection and radiation, extremely appealing due to their ease of use, reliability, and efficiency. To enhance the system's performance, the experimental investigation utilized different fin shapes, including plain, pin fin, and ribbed fin, under uniform heat flux conditions and surface emissivities of 0.85 and 0.09, for both coated and uncoated surfaces. The result indicates that the maximum average convective and radiation heat transfer coefficient for ribbed with black coated fin was 7.8 and 3.2 Wm⁻²&#xa0;K⁻¹, and the convective and radiation Nusselt numbers were 25.2 and 10.4, respectively. In the same configuration, the effectiveness of the fin was found to be 2.48, which is 13% and 8% higher than that of the coated and uncoated plate fins, respectively. Comparing only fins, the convective and radiative heat transfer coefficients for a ribbed fin range are 16 to 24% higher than those for the remaining two fins. The enhancements are primarily attributed to the combined effects of the enhanced surface emissivity from the black coating and the increased surface area from ribbing, which together stimulate better radiative heat transfer and natural convection. The results of the experiment unequivocally demonstrate that, in natural convection settings, both fin geometry and surface emissivity are crucial factors in enhancing heat dissipation efficiency.</p>