One of the models for the formation of the G4 is the transition between two states: a single strand in the absence of ions and a fully folded G4 in the presence of an excess concentration of potassium ions. However, the frequencies associated with guanine carbonyl stretching in the EVV 2DIR spectrum of Myc2345 in the absence of ions are not characteristic of that of guanine in a single strand. Nonetheless, the formation of a higher order structure in response to the addition of potassium ions is indicated by a number of observations, namely, the red-shift of the guanine carbonyl stretch frequencies, the observed changes in cross-peak intensities and the appearance of two new couplings. To gain a better understanding of the structure observed in the absence of ions and the observed spectral changes upon increasing ion concentration, we calculated EVV 2DIR spectra for the G4 and its possible precursors. The details of the calculation methodology are provided in the Methods section, but we note here that we have in this work not included the so-called mechanical anharmonicity contribution to the expressions for the spectral intensities , and the calculated spectra are therefore only based on the electrical anharmonicity contribution, here involving second-order derivatives of the molecular dipole moment. We furthermore note that we have employed a uniform scaling parameter for the vibrational energy levels, which were calculated harmonic vibrational potential approximation, and thus not considered any difference between overtone/combination band energy levels and the corresponding sum of one-quantum energy levels. Finally, we remark that the calculations have been carried out in vacuo, not involving any implicit or explicit solvation while the experimental sample existed in the presence of abundant water. Altogether, the level of confidence in the findings associated with the analysis of the quantum-chemical calculations in this work should therefore be considered with these limitations in mind. The overall strategy in this work is to identify and distinguish three possible structure types. These are isolated guanines which are not part of a quartet; guanines arranged in a quartet and guanine quartets stacked to form a G-quadruplex.