A family of five hybrid ABX perovskites has been synthesized using hypophosphite (HPOO) as the X-site ion. These compounds adopt the general formula [Am]Mn(HPOO), where Am = guanidinium (GUA), formamidinium (FA), imidazolium, triazolium, and dabconium. We explore the diverse structural and phase transition behavior of these materials through single-crystal diffraction measurements and demonstrate contrasting magnetism in two of the phases, Am = GUA and FA, that arises from structural distortions. The results show that hypophosphite perovskites offer a promising platform for generating new functional materials.