Dimethyl 2,6‐dimethyl‐4‐oxo‐4H‐chromen‐3‐yl‐phosphonate (1a) and dimethyl 6‐methyl‐2‐phenyl‐4‐oxo‐4H‐chromen‐3‐yl‐phosphonate (1b) were synthesized and reacted with primary aliphatic amines to yield title compounds 4—6. Their antibacterial properties against Gram‐positive and Gram‐negative bacteria strains were tested by the MIC method. Four of seventeen tested compounds (1d, 3, 4a, and 4b) exhibit detectable activity against S. aureus. Some representative examples of newly synthesized compounds were tested for their alkylating properties in vitro in the Preussmann test. Compounds 1a, 1c, 1d, 3, 5d, and 6a possess highly alkylating activity toward standard derivative 4‐(4'‐nitrobenzyl)pyridine (NBP).