1,4 Dihydropyridines: Synthetic Methodologies, Green Advances, and Expanding Pharmacological Horizons

1,4 Dihydropyridines (1,4 DHPs) constitute one of the most versatile and pharmacologically significant scaffolds in heterocyclic chemistry. Since their first synthesis by Hantzsch in 1882, they have evolved from synthetic intermediates to a cornerstone of medicinal chemistry, underpinning a wide array of bioactive compounds. This review provides a critical and comprehensive account of their structural features, structure–activity relationships, and classical as well as modern green synthetic methodologies, including multicomponent, solvent free, and nanocatalytic approaches. Particular emphasis is placed on microwave and ultrasound assisted eco friendly protocols that align with current sustainability goals. The diverse pharmacological profile of 1,4 DHPs—ranging from calcium channel blocking activity in antihypertensives to emerging anticancer, antimicrobial, neuroprotective, and antioxidant potentials—is systematically highlighted with representative examples. Together, these insights showcase 1,4 DHPs as a privileged motif at the intersection of synthetic innovation and drug discovery, with far reaching implications for future therapeutic development and green chemistry.