Poly(vinyl cinnamate) (PVCN) could undergo thermal or photo crosslinking. PVCN was previously found to be miscible with poly(vinyl phenol) (PVPh) [also named poly(hvdroxystyrene)]. In this article, the miscibility between PVCN with or without thermal crosslinking and poly(styrene-co-hydrostyrene) (designated as MPS) was investigated. PVCN was determined to be miscible with MPS with 15% of hydroxystyrene (MPS-15) at two compositions but partially miscible or immiscible at PVCN/MPS-15-(50/50) composition. For MPS with 5% of hydroxystyrene (MPS-5), two T-g values were detected indicating mostly immiscibility. However, PVCN after thermal crosslinking was determined to be miscible with both MPS-5 and MPS-15. Immiscibility was found between thermally crosslinked PVCN and PVPh different from miscibility in the original PVCN/PVPh blends. (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 108: 900-903, 2008.