Phenylethanethiol protected nanomolecules such as Au-25, Au-38, and Au-144 are widely studied by a broad range of scientists in the community, owing primarily to the availability of simple synthetic protocols. However, synthetic methods are not available for other ligands, such as aromatic thiol and bulky ligands, impeding progress. Here we report the facile synthesis of three distinct nanomolecules, Au-38(SCH2CH2Ph)(24), Au-36(SPh-tBu)(24), and Au-30(S-tBu)(18), exclusively, starting from a common Au-n(glutathione)(m) (where n and m are number of gold atoms and glutathiolate ligands) starting material upon reaction with HSCH2CH2Ph, HSPh-tBu, and HStBu, respectively. The systematic synthetic approach involves two steps: (i) synthesis of kinetically controlled Au-n(glutathione)(m) crude nanocluster mixture with 1:4 gold to thiol molar ratio and (ii) thermochemical treatment of the purified nanocluster mixture with excess thiols to obtain thermodynamically stable nanomolecules. Thermochemical reactions with physicochemically different ligands formed highly mono dispersed, exclusively three different core-size nanomolecules, suggesting a ligand induced core-size conversion and structural transformation. The purpose of this work is to make available a facile and simple synthetic method for the preparation of Au-38(SCH2CH2Ph)(24), Au-36(SPh-tBu)(24), and Au-30(S-tBu)(18), to nonspecialists and the broader scientific community. The central idea of simple synthetic method was demonstrated with other ligand systems such as cyclopentanethiol (HSC5H9), cydohexanethiol(HSC6H11), para-methylbenzenethiol(pMBT), 1-pentanethiol(HSC5H11), 1-hexanethiol(HSC6H13), where induced core-size conversion and Au-36(SC5H9)(24), Au-36(SC6H11)(24), Au-36(pMBT)(24), Au-38(SC5H11)(24), and Au-38(SC6H13)(24) were obtained, respectively.