The primary product of this enzyme is 4,2',4',6'-tetrahydroxychalcone (also termed naringenin-chalcone or chalcone) which can under specific conditions spontaneously isomerize into naringenin. 4-coumaroyl-CoA + 2 H(+) + 3 malonyl-CoA = 2',4,4',6'-tetrahydroxychalcone + 3 CO2 + 4 CoA Secondary metabolite biosynthesis; flavonoid biosynthesis. CHSF does not appear to be pseudogene, but expression of this gene could not be detected in various floral tissues nor in seedlings after illumination with UV light. Belongs to the thiolase-like superfamily. Chalcone/stilbene synthases family.