Substituted 3-phenyl,7-methoxy-benzopyran derivatives and vitamin D3 (cholecalciferol, 1) were evaluated for their estrogen agonistic and antagonistic activities in immature female Sprague–Dawley rat model. The benzopyran derivatives 17 and 18, which were made as hybrids of estrogen and vitamin D3 (pseudo vitamin D3 analogs), showed significant estrogen agonistic activity (up to 48%) and weak estrogen antagonistic activity (up to 6%) at 10 mg/kg, whereas vitamin D3 showed significant estrogen agonistic (82%) and antagonistic activities (39%) at 10 mg/kg.