This invention relates to conjugated diene phosphinate compounds for making halogen free phosphinate-containing flame retardants, inimer and metal extractants, method for preparing said compounds from unsaturated ketones or aldehydes, and the 5 use thereof. The compounds of the present invention having the following formula (III), wherein R1, R2, R3, R4, R5 and R6 represent, independently, hydrogen, alkyl, aryl, alkaryl, aralkyl, cycloalkyl, heterocycloalkyl, or alkenyl groups; R7 represents hydrogen, alkyl, aryl, alkaryl, aralkyl, cycloalkyl, alkenyl groups, or metals selected from the group consisting of Na, Li, Ca.