I research how sustainability messages move markets. Drawing on the S–O–R framework, the Advertising Value Model, and flow theory, I examine which ESG ad elements—such as entertainment, credibility, and message relevance—shift attitudes and purchase intention across social-media contexts. Methodologically, I focus on rigorous measurement: CFA/SEM, mediation with bootstrap confidence intervals, and discriminant-validity diagnostics (HTMT alongside Fornell–Larcker). Recent work maps two pathways from message design to intention: an attitudinal route via advertising value and a rapid, immersive route via flow. My goal is to turn ESG disclosure into clear behavioral insights that help organizations communicate responsibly while sustaining performance. Keywords: ESG advertising; sustainability communication; consumer behavior; S–O–R; advertising value; flow; CFA/SEM; mediation; HTMT.