Recent progress in the molecular design and synthesis of high-performance organic photovoltaic materials has resulted in a remarkable enhancement of power conversion efficiency, surpassing the 20% benchmark in single-junction devices, largely driven by the development of non-fullerene electron acceptors [1]. Despite the success of Y6 and its derivatives, fused-ring electron acceptors continue to suffer from complex, multistep synthetic routes and low-yield ring-closure reactions, which substantially challenge organic solar cells large-scale production and commercialization [2]. To address these limitations, the advent of non-fused-ring electron acceptors has emerged as a promising alternative due to their competitive photovoltaic properties, facile synthesis, and high yields, enabling the fabrication of cost-efficient devices [3]. These materials simplify conventional fused-ring architectures by substituting rigid polycyclic frameworks with simpler three-ring or mono-/bi-cyclic units connected through single σ-bonds, typically adopting an acceptor–π–donor–π–acceptor configuration. In this work, a pair of fluorene-based acceptors, FHM-Cl and FHM-F, respectively featuring a chlorinated and a fluorinated 1,1-dicyanomethylene-3-indanone end group, π-bridged through alkyl-substituted thiophene units to a fluorene core, were synthesized through a three-step route from commercially available precursors. Organic solar cells utilizing these acceptor molecules were subsequently fabricated and optimized with various donor materials. Notably, the combinations D18:FHM-Cl and D18:FHM-F achieved PCEs of 10.7% and 7.6%, respectively. A comprehensive study involving optical and electrical characterization, along with morphological analysis, demonstrated that the FHM-Cl-based solar cells exhibited superior light absorption, enhanced solid-state packing and reduced trap-assisted recombination. Moreover, the good shelf and thermal stability of the devices further highlight the potential of these acceptors for the design of low-cost and efficient organic solar cells, with FHM-F- and FHM-Cl-based devices showing efficiency losses of only 15% and 25%, respectively, after 950 h of thermal aging at 65 °C. Owing to their favorable absorption profiles and wide bandgaps, these novel acceptor molecules also show potential for application in indoor photovoltaic systems and in ternary device architectures.