Sixteen 1,3,5-triphenyl-2-pyrazolines were synthesized and their anti-infective activities (against Mycobacterium tuberculosis H37Rv, six bacterial and four fungal strains) were tested. Only compound with SO2CH3 in the para position of the A-ring was active against the tubercular strain at 100 μg/ml concentration. All compounds showed good anti infective activity against Escherichia coli and poor activity against Staphylococcus aureus. Compounds 4, 12, 13 and 14 exhibited reasonable activity against all the organisms tested (<0.309 μM except against S. aureus. The activity of these compounds correlated with their lipophilic/hydrophilic nature. Compounds 4, 10 and 16 showed very good activity (>88% reduction) against four fungi studied at 2 mg/ml. All these compounds possess halogen substitutions. Compound 11 showed very high activity (>90%) against three fungi. Majority of the compounds showed more than 90% inhibition against one or two fungi. Since pyrazolines are reported to inhibit the activity of p-glycoprotein, they may prevent drug resistance developed by microorganism. © 2010 Elsevier Ltd. All rights reserved.