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An asymmetric squaraine sensitizer comprising an anchoring group was engineered at the molecular level and synthesized. The functionalized novel squaraine sensitizers upon anchoring onto a TiO₂ film exhibit an unprecedented incident photon to current conversion efficiency of 85%. The photovoltaic data of this sensitizer using an electrolyte having composition of 0.6 M M-methyl-N-butyl imidazolium iodide, 0.05 M iodine, 0.1 M LiI, 0.05 M tert-butylpyridine in a 15/85 (v/v) mixture of valeronitrile and acetonitrile revealed a short circuit photocurrent density of 10.5 ± 0.2 mA/cm², an open circuit voltage of 603 ± 10 mV, and a fill factor of 0.71 ± 0.02, corresponding to an overall conversion efficiency of 4.50% under standard AM 1.5 sunlight.