The dataset contains the numerical data used to produce the simulated data represented in the figures and tables of the article "Electronic spin relaxation in triangulene-based nanographenes". Authors: Alicia Omist and Roberto A. Boto. Journal: Theoretical Chemistry Accounts Reference: Theor. Chem. Acc, 144, 70 (2025) DOI: https://doi.org/10.1007/s00214-025-03223-3 ---- General comments ----The data files are organized in different folders and subfolders corresponding to each of the figures, subfigures and tables showed in the main text and SI of the article. The following file formats are used in the data set: FigureZ.dat: Simulated data computed within DFT. The data in the first and second columns correspond to the data depicted in the x and y-axis, respectively, showed in the figures of the article. The letter "Z" in the title of the file stands for the label of the corresponding figure in the article. X_optfreq_m062x631gdp.log: Output file obtained with the software Gaussian 16. Rev.B.01. The data in this file correspond to the result of the DFT calculations (UM062X/6-31g(d,p)) carried out to obtain the minimum energy structures used in the article. The letter X in the name of the file corresponds to the name of the molecule. X_freq_m062x631gdp.log: Output file obtained with the software Gaussian 16. Rev.B.01. The data in this file correspond to the result of the DFT calculations (UM062X/6-31g(d,p)) carried out to obtain the vibrational properties for the minimum energy structures used in the article. The letter X in the name of the file corresponds to the name of the molecule. X_spindensity_m062x631gdp.cube: Gaussian cube files corresponding to the spin density for the molecules 3-Rho1 and CG1 shown in Figure 1c and 1d of the article, respectively. X_gtensor_Y.out: Output file obtained with the software ORCA 5.0.3. The data in this file correspond to the result of the DFT calculations (at the theory level "Y"= exchange-correlation functional/basis set) carried out to compute the g tensors used in the article. The letter X in the name of the file corresponds to the name of the molecule. X_hfi_Y.out: Output file obtained with the software ORCA 5.0.3. The data in this file correspond to the result of the DFT calculations (at the theory level "Y"= exchange-correlation functional/basis set) carried out to compute the hyperfine coupling tensor used in the article. The letter X in the name of the file corresponds to the name of the molecule. X_zfs_Y.out: Output file obtained with the software ORCA 5.0.3. The data in this file correspond to the result of the DFT calculations (at the theory level "Y"= exchange-correlation functional/basis set) carried out to compute the zero-field splitting tensor used in the article. The letter X in the name of the file corresponds to the name of the molecule. Further information is provided in the first lines of each data file.