We focus on a theoretical investigation using the DFT and LC–SCC–DFTB for investigating the structural, optical and reactivity properties and electronic structure of pristine graphdiyne (GDY) and nitrogen (N)-doped hexagonal carbon rings of GDY nanomaterials. Our calculations show that the energy gap (E g) of the GDY is 1.00 eV which is excellent agreement with the DFTB. By increasing the content of N, the E g changes in the wide range of 0.15–0.98 eV. The absorbance maxima are at 1.91 eV (647 nm) for the GDY, 1.46 eV (845 nm) for the N-GDY, 2.15 eV (576 nm) and 1.21 eV (1020 nm). The decrease in the value of the E g with temperature for the GDY and 3 N GDY is observed due to variations of the bond energy which reflects the E g. However, an increase in the value of the E g with temperature is found linearly for the N-GDY because the Fermi energy level is pushed higher from− 3.722 to− 4.027 eV. The dipole moment increases when increasing the content of N and temperature. Obtained results herein suggest the GDY and N-doped GDY nanomaterials can be used as very promising advancements for potentially useful optoelectronic novel applications.