Microbial infections are a constant threat to humans and responsible for increased death rate in most of the developing countries. Conventional use of chlorine- or alcohol-based disinfectants results in the development of drug-resistant microbial strains, which are limited in their response to most of the treatment strategies. In this perspective, several engineered materials have emerged as an affordable alternative to the existing treatment strategies. For the same, here we have synthesised CuI microparticles (CuI (WH) and CuI (H)) using chemical precipitation followed by a hydrothermal process. We further comparatively evaluated the antiproliferative activity of CuI (WH) and CuI (H) against microbial cultures (non-resistant and resistant), virus, and cancer cell lines. CuI (H) displayed better size, stability, and significantly higher inhibitory activity against microorganisms and cancer cell lines than CuI (WH). Upon preliminary evaluation, which confirmed that CuI (H) is more effective than CuI (WH), we evaluated its stability and surface sterilising property, and it was found that CuI (H) were stable for the recorded period of 30 days and displayed significant surface sterilising ability. The results suggest that CuI (H) is a potent antiproliferative material against microbial cultures, viral strains, and cancer cell lines while preserving its biocompatibility towards normal cell lines, representing a potential surface sterilising material in public places upon significant in vivo efficacy evaluation. © 2023 RSC