Composite photoanode comprising mesoporous microspheres with a smooth spherical morphology exhibiting high light scattering due to optical whispering gallery modes (WGMs) is used to fabricate whisperonic solar cell (WSC) devices. The photoanode is sensitized with CdS-CuInS 2 thin films (CdS-CIS-TF) of ∼5 nm thickness. CdS-CIS-TF-sensitized photoanodes exhibit strong coupling with WGM. These WSC devices show an average (η avg ) efficiency (η) of ≈3.2% in comparison with η avg ≈ 1.9% for the nanoparticulate-based photoanode. The observed efficiency is the highest for CdS-CIS-TF-sensitized solar cells made using I - /I 3 - electrolyte. This remarkable increase in η avg (∼60%) is attributed to increased photon absorption by the sensitizer films because of the presence of WGM scattering prevailing in smooth microspheres. Thus, WSC photoanode configuration is a promising approach to enhance the efficiency of TF-sensitized solar cells. © 2019 American Chemical Society.