A first-principle study of the structural diversity and optoelectronic properties of the small penta-graphene quantum dots (PGQDs) has been performed. The stability and optoelectronic properties of the PGQDs are investigated under the effect of chemical modifications. PGQDs are edge functionalized by non-metallic atoms (Si, P, O, F) such as identical edge termination (Si-PGQD, P-PGQD, O-PGQD, F-PGQD) and alternate edge termination (Si-O-PGQD, H-P-PGQD). Further, H-PGQDs are also doped and co-doped with B and P atoms. All studied structures are stable with strong electronic quantization and exhibit semiconducting or metallic properties depending on the termination, doping elements and their site. Absorption peaks in the visible region were not observed for hydrogen passivation PGQDs. However, some absorption peaks appear in this region for edge-passivated. In addition, there are dramatic changes in the electronic properties of B, P, BP-doped PGQDs to give peak shifts to the visible region from the ultraviolet region of the pure sample due to hybridization effects. The enhanced reactivity, controllable electronic properties of edge passivation, and doping make PGQDs ideal for new nanodevice applications.