In the present studies, two series of 4-substituted-imidazolidines (IIIa-i and IIIj,k) were synthesized by reacting different tetrahydro-di-Schiff bases (IIa-i and IIj,k) with p-diethylaminobenzaldehyde/ dimethylaminobenzaldehyde. The title compounds were evaluated for their antibacterial and antifungal actions against some selected microbes. The results of microbiological evaluation revealed that two compounds, 4-(1,3-bis(benzo[d][1,3]dioxol-5-ylmethyl)-4-methylimidazolidin-2-yl)-N,N-diethyl aniline (IIIj), 4-(1,3-bis(benzo[d][1,3]dioxol-5-ylmethyl)-4-methylimidazolidin-2-yl)-N,N-dimethyl aniline (IIIk) were good in their antibacterial as well as antifungal actions. Minimum inhibitory concentration values (MIC) of the compounds are reported.