Intrinsically disordered proteins (IDPs) or proteins containing intrinsically disordered regions (IDRs) are abundant in over half of the eukaryotic proteome. While significant efforts have been devoted to studying these proteins' structure and function relationships, the evolutionary origins and mechanisms behind the formation of their current forms and sequences remain elusive. NMR spectroscopy is the primary tool for investigating IDPs/IDRs at a residue-specific level. I will present our recent works applying this technique to study the potential evolutionary routes of IDPs/IDRs through two examples: (1) The Musashi protein family's paralogs demonstrate that the IDRs may have evolved divergent physicochemical characteristics but for the same ability, such as liquid-liquid phase separation. (2) The IDR-tagged galectin orthologs among vertebrates show the convergent evolution of using different sequence motifs in IDRS for the agglutination functions.