Three dendritic molecules EG0, EG1 and EG2 were synthesized and separately used as co-adsorbents in dye-sensitized solar cells (DSSCs) to explore their effect on controlling interfacial charge recombination. It was found that the resulting device with EG2 as the co-adsorbent (device EG2) displayed superior open-circuit voltage (VOC), improved short-circuit current density (JSC) and a higher power conversion efficiency (PCE) of 7.50%, as compared to the control device (N719) and the devices with EG0 or EG1 as the co-adsorbent (devices EG0 and EG1). Such improved performance is ascribed to the increase of the interfacial distance upon the introduction of EG2, and the formation of a more compact monolayer of the dye N719 and co-adsorbent EG2 at the interface, which shields the acceptors in the electrolyte from contacting the TiO2 surface, hence reducing the back current and increasing the VOC. On the other hand, the aggregation of dye molecules is restrained due to the competitive adsorption between dye N719 and co-adsorbent EG2, thus leading to the minimization of energy loss and the enhancement of JSC. As a co-adsorbent, EG2 was also introduced to DSSCs using either the iodide electrolyte without the additive 4-tert-butylpyridine (TBP) or the cobalt electrolyte. The results showed that EG2 also displayed effective capability of suppressing interfacial charge recombination and reducing intermolecular energy transfer.