This invention provides a plant growth regulatory activity of a new biologically active synthetic molecule methanone-(3′,4′,5′-trimethoxy) phenyl, 1-naphthyl, 2-O-4″-ethyl but-2″-enoate. More particularly, the invention relates to the potent plantgrowth promoting activity of a gallic acid derivative having a structure represented by Formula 1 and a molecular formulae C26H26O7. This invention also provides a novel process for preparation of said molecule from a naturally occurring compound and testing it for growth regulating activity using Bacopa test system developed at CIMAP (Khanuja et al., 2001).