The quinazoline nucleus is an interesting molecule in the major class of two nitrogen atoms in the structure of aromatic cyclic compounds. Quinazolines and fused quinazolines have attracted the attention of medicinal chemists because of their potential biological activities. In this study, we address the design, synthesis, and evaluation of anti-breast cancer inhibitory activities of quinazoline derivatives. Breast cancer is the second leading cause of cancer-related deaths in women worldwide. Microbial infections: Emerging infectious diseases are diseases with an infectious cause. Their incidence has increased in the recent past and threatens to increase further in the near future. The potential activities of quinazoline derivatives against protein 3RCD are analysed with Glide software (Schrödinger Suite 2018–1) docking programmes and compared with the standard drug tamoxifen. The results of the in silico studies provide compelling evidence for the reflection of valuable ligands in quinazoline derivatives as potential HER2 inhibitors, and compounds A1b, A1c, A2c, A2d, B1c, B2db, B2c, B3a, B3c, and B3e with significant binding energy may generate significant antibreast activity for further development that may prove their therapeutic potential.