Celery and coriander are vastly applied in modern medicine and traditionally because various medicinal and nutritional benefits depend on their medicinal characteristics. The study aimed to detect, isolate and compare extracts contents of phenolic acids (caffeic and p-coumaric acids) in ethyl acetate fraction of fresh and dry aerial parts of coriander (Coriandrum sativum L.) and celery (Apium graveolens L.) of the Apiaceae family. The extraction of these constituents was carried out by maceration method using 70% ethanol and fractionation was done by using petroleum ether, and ethyl acetate. The existence of caffeic and p-coumaric acids in aerial part extracts of two plants was identified by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). After qualitative determination of these active constituents, high-performance liquid chromatography analysis was also applied for quantification of caffeic and p-coumaric acid and the results showed that ethyl acetate extract of dry coriander showed higher contents of caffeic and p-coumaric acid than ethyl acetate extracts of fresh coriander and celery (dry and fresh). Depending on the results of TLC and HPLC, two bioactive compounds (caffeic acid and p-coumaric acid) were isolated and identified by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and full scan product ion mode liquid chromatography mass spectrometry. This result opens the minds to the dry plant era and leads to counter fiction of what was known that fresh plant gives better results than the dry one.