Cedrelone was isolated from Toona ciliata heart wood and the compound was modified with various chemical reagents and the resultant product was characterized by IR, 1H NMR, 13C NMR and Mass spectra. The synthesized compounds were screened for antimicrobial activities and the zone of inhibition was ascertained by disc diffusion method. The microorganisms selected for the study was Gram positive organisms such as a) Staphylococcus aureus (ATCC 9144), b) Staphylococcus epidermitis (ATCC 155), c) Bacillus subtilis (ATCC 6633), d) Bacillus cereus (ATCC 11778), e) Micrococcus luteus (ATCC 46789) and Gram negative organisms a) Escherichia coli (ATCC 25922), b) Pseudomonas aeruginosa (ATCC 9027). Fungi organism a) Candida albicans (ATCC 1091), b) Aspergillus niger (ATCC 6275). Cedrelone and its derivatives exerted pronounced inhibitory response against all the species of bacterial organism tested, except E. coli. Bromohydroxy cedrelone and Michael adduct showed good antifungal activity.