[Objective] This study aimed to synthesize novel thiourea derivatives with good antimicrobial activities. [Methods] Thiourea derivatives were synthesized through condensation of various primary amines with the α-isothiocyanatoacrylic ester (ICE) intermediate; their structures were determined by MS and NMR analysis and their antimicrobial activities were then evaluated. [Results] Six novel thiourea derivatives and one new α-isothiocyanatoacrylic ester derivative were synthesized through condensation of corresponding primary amines with α-isothiocyanatoacrylic ester. The bioactivities of these compounds were tested against several representative pathogenic bacterium and fungus strains. Specifically, the thiourea derivatives showed considerable inhibition activities against Cryptococcus neoformans, the pathogen fungus of cryptococcosis. [Conclusion] Synthesis of new thiourea derivatives and test their biological activities is a potential way to discover small molecule drug leads.