Electrodeposition of CuSbS2 semiconductor thin films for photovoltaic solar cells is investigated from ionic liquid electrolyte based on choline chloride-urea eutectic. Cyclic voltammetry study shows Cu and Sb deposition potential of -0.54 V and -0.48 V vs Pt, respectively. Highly crystalline CuSbS2 films in the chalcostibite orthorhombic structure without binary compound phases are electrodeposited at a potential of -0.65 V vs Pt with Cu to Sb precursor ratio of 1:1 and Na2S2O3 as sulfur source in ionic liquid medium held at 80 degrees C. Increase in Cu-precursor ratio (1:0.71) led to Cu3SbS3 ternary and that of Sb-precursor ratio (1:1.4) led to binary Sb2S3 phase inclusion in the phase field of the CuSbS2 films. Electrochemical impedance spectroscopy studies show diffusive ionic transport limited growth mechanism. Single phase CuSbS2 films show direct band gap energy of 1.66 +/- 0.01 eV and films with inclusive secondary phases have band gap energy of 1.73 +/- 0.01 eV. As-deposited CuSbS2 films are p-type and a hetero-junction in the nZnO-pCuSbS(2) structure showed rectifying current-voltage behavior and low reverse current consistent with compact pinhole free CuSbS2 film synthesized by ionic liquid electrodeposition. (C) 2014 Elsevier B.V. All rights reserved.