A novel series of eleven 4-(4-(1H-imidazol-1 yl)phenyl)-6-arylpyrimidin-2-amines has been prepared from synthesized 3-[4-(1H-imidazol-1-yl) phenyl]prop-2 en-1-ones and evaluated for phosphodiesterase (PDE) inhibition and antimicrobial activities. N-arylation of imidazole with 4-fluorobenzaldehyde using hexadecyltrimethylammonium bromide as catalyst gave 4-(1H-imidazol-1-yl) benzaldehyde which on treatment with substituted acetophenones yielded corresponding chalcones (1a–1k). Each chalcone on further reaction with guanidine hydrochloride resulted in title compounds (2a–2k). Pyrimidines thus synthesized were subjected to biological studies. Some compounds showed marked activities in PDE inhibition and anti-bacterial and anti-fungal bioassays.