The United Nations Convention on the Rights of Persons with Disabilities (UN CRPD) (2016) places further emphasis on the priority of communicative accessibility that integrates accessible multimedia and assistive technology, based on the recognition of the centrality of universal design for accessibility. However, when dealing with museum accessibility issues, multimedia content, and assistive technology are often discussed separately as two individual topics. Actually, it is more efficient to address accessibility concerns when they are presented together, especially in relation to communicative accessibility. This study aims to investigate how assistive technologies can support communication in different multimedia forms through cross-sensory information for people with sensory impairments (PwSI) in the context of museum accessibility and to further design reflections for communicative accessibility of technology-based multimedia content in different sensory modalities. First, this study investigates the types of technologies available to access different multimedia information for PwSI and their functional motivations. As a result, a framework for presenting the relationship between assistive technology, multimedia, and sensory representatives is proposed. It can serve as an analytical structure for researchers to outline cases, as well as design references for museums to gain insights into accessibility for better communication. As an example of its application for analysis, a case study of one of the few museums with exceptional accessibility practices among communication museums is performed. Ultimately, we emphasize the necessity of technology being well-designed to support accessibility.