2- Ethoxy-4(3H) quinazolinone 1 was synthesized and allowed to react with various halides, namely: alkyl, benzyl, allyl, acyl, haloacetyl, crotonyl, benzoyl, 2-furoyl and 1-naphthalenesulphonyl halides affording quinazoline and quinazolinone derivatives. The reactions of compound 1 with phosphorus oxychloride, phosphorus pentasulfide, ethyl chloroformate, ethyl chloroacetate, ?-bromoglucose tetraacetate, p-acylaminobenzenesulfonyl chloride, acrylonitrile, chalcone and chalcone oxide were also investigated. Depending on the reaction condition and reactant halide, the type of substituent (alkyl, acyl, aroyl, etc.) that will reside on either of the expected positions (3 or 4) on the quinazoline moiety can control the reaction pathway for synthesis of the promising products. The significant role of solvent responsible for determining both the reaction pathway and type of products synthesized was also discussed. Some derivatives were chosen for biological screening test against Gram (-ive) and Gram (+ive) bacteria and two strains of fungi.