Disclosed herein are the methods and compositions for the improved synthesis of texaphyrin metal complexes. The improved synthesis results in high-purity compositions of texaphyrin metal complexes in which more than about 98% of the texaphyrin metal complexes in the composition have the same structure and/or the same molecular weight. Further described herein are pharmaceutical compositions comprising such high-purity compositions, and the use of such high-purity compositions in the treatment of cancer and cardiovascular diseases and disorders.