Here, we are reporting interface engineering to create designed heterojunctions in Cu2ZnSnS4-rGO-MoS2 (CZTS-reduced graphene oxide-MoS2), in which abundant high density of nanoscale interfacial contacts are formed. It has been achieved via two-step optimized electrodeposition approach. Further, as-prepared materials have been characterized by microscopic, spectroscopic and electroanalytical techniques. Finally, the concept of generation of designed heterojunctions and synergetic effect were tested for electrocatalytic and photoelectrocatalytic hydrogen generation. The electron-hole pair recombination has been reduced, since the fast transport of photoexcited electrons of CZTS to MoS2 through reduced graphene oxide interfacial contacts. Further, the synergetic effect of increased charge separation between rGO and more catalytically active sites from MoS2 has been attributed to enhanced hydrogen generation. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.