The paper uses a two-dimensional heat conduction model to obtain the thermal performance and entropy generation in an orthotropic pin fin used in advanced light weight heat sinks. The analytical expressions for the distribution and heat transfer rates are used to generate the thermal performance graphs that are of general applicability unlike the results for specific cases reported so far. The same information is subsequently used to generate graphs of local and total volumetric entropy generation rates in the fin. The results clearly delineate the effect of radial Biot number, fin aspect ratio, and the ratio of radial to axial thermal conductivities on temperature distribution, heat transfer rate, and local and total entropy generation rates. A procedure is discussed to illustrate the simultaneous realisation of the least material and minimum entropy generation pin fin designs.