In this study, the design, synthesis and preliminary pharmacological investigation of novel 1,3-diethyl-8-disubstituted xantines 12-18, 1,3,6-trisubstituted-1H-thiazolo[3,2-f]purine-2,4diones 19-25 and xanthine Schiff bases 28-33 was described. 1,3-Diethyl-8-substituted xantines 12-18 were prepared by the reaction of 1,3-diethyl-8-thioxo-3,7,8,9-tetrahydropurine-2,6-dione 4 with the appropriate phenacyl bromides 5-11. Compound 4 was in turn prepared by the reaction of 5,6-diamino-1,3-diethyluracil 3 with carbon disulfide. The derivatives 19-25 were obtained by cyclodehydration of compounds 12-18 in polyphosphoric acid (PPA). Schiff bases 28-33 were synthesized by the reaction of acetohydrazide 27 with appropriate aldehyde in refluxed ethanol. The effect of the new derivatives as potential anti-asthmatic was evaluated using acetycholine induced brocnhospasm in Guinea pigs, most of tested compounds showed significant anti-bronchoconstriction activity in comparison with aminophylline as a standard drug. Anti-inflammatory activity of the target compounds was investigated using indomethacin as a reference drug and some compounds exhibited potent anti-inflammatory activity.