PVDF, one of the most versatile fluoropolymers, is inert and is difficult to functionalize using conventional approaches. Herein, we attempted a facile and one-pot modification of PVDF via ozonization process. The ozone treated PVDF facilitates in harnessing suitable functional moieties. Using this strategy, two copolymers were designed to achieve crystalline-amorphous and crystalline-crystalline grafts. Their effects on phase transformation, dielectric and piezoelectric behaviors of PVDF were systematically investigated. The microstructure and phase transformation of this modified PVDF copolymer was characterized by XPS, XRD, FTIR, SAXS, and DSC. FTIR results revealed that the extent of polar  phase increased from 38 % in untreated PVDF to 84 % after ozonization. Interestingly, the enhancement is more pronounced after grafting. For instance, after grafting a crystalline polymer, poly (butylene succinate-co-adipate) (PBSA) onto PVDF near-complete transformation from  to  phase (96 %) was observed. This was attributed to the specific covalent interaction between the -OH group in PVDF-OH and –COOH groups of PBSA. This strong covalent interaction helps to align the PVDF chains in trans conformation and as a result more  phase crystals are formed. The long period (Lw) calculated from SAXS for an amorphous graft as in PVDF-g-poly(methyl methacrylate-co-acrylic acid) (PMM-co-AA) and PVDF-g-PBSA decreased significantly as compared to neat PVDF. The remarkably enhanced  phase in the grafted polymers reflected in higher dielectric constant and piezoelectric coefficient (d33) as compared to untreated PVDF. For instance, the PVDF-g-PBSA copolymer showed higher piezoelectric and dielectric constant with low dielectric loss as compared to untreated PVDF. This study attempts to address whether the nature of graft (crystalline vs amorphous) decides the extent of β-PVDF and piezoelectric properties in PVDF copolymers.