Organic solar cells, as a new type of solar cell, possess outstanding advantages such as light weight, low cost, and easy large-scale fabrication. They have attracted significant attention in both the academic and industrial fields. In recent years, the energy conversion efficiency of polymer solar cells has increased rapidly, and the efficiency value of single-junction devices has exceeded 19%. In material design, developing high-performance mid-bandgap acceptor materials has become an important strategy for improving the efficiency and stability of organic photovoltaic devices. Therefore, by introducing electron-donating units at the side chains and termini of the Y series acceptor molecules, we weakened the charge transfer effect within the acceptor molecules and developed a series of high-performance mid-bandgap acceptor materials. These materials were applied to the construction of efficient organic photovoltaic systems. Among them, the photovoltaic device based on the PM6: PYFO-V system achieved the highest indoor photoelectric conversion efficiency of 27.1% under LED illumination, which is one of the highest values reported for binary indoor full-poly systems to date; moreover, a ternary organic photovoltaic system using BTP-2FClO and BTP-eC9 as non-fullerene acceptors achieved a high efficiency of 19.34% under sunlight. This series of work has opened up new ideas about how to modify the molecular design of mid-bandgap acceptor materials in the future and provided material support for the development of high-efficiency solar cells.