Serial verb constructions (SVCs) have been extensively described in oral languages and are also productive in sign languages. These are characterized as multi-verb sequences without manifestation of a coordinator or subordinatior element. These sequences share functional marker related to tense, aspect and negation, and the external and the internal arguments. They denote a single event and have monosentential prosody. The aim of this work is to present a characterization of SVCS, based on crosslinguistic and intermodal data, proposing a formal analysis for the phenomenon built upon first-hand data from Libras. Two grammaticality judgment tasks using the playback technique were conducted with the participation of native Libras signers, addressing both symmetric and asymmetric SVCs. Our observations indicate, firstly, that multiverb sequences in Libras are distinct in semantic and syntactic terms when compared to overt and covert coordinated sentences. SVCs proved to be productive in Libras and exhibited restrictions like those documented in the literature for oral languages and other sign languages. Sandwiched SVCs are also productive in Libras, but despite sharing some similarities with SVCs in other sign languages, behave differently, functioning as focus structures with verbal reduplication. Sequences of AB verbs with change of perspective, while less productive, were also observed. These contrast with conventional passive structures, resembling more complex predicate structures. Based on the theoretical and typological literature and on the data collected in Libras, we adopted a syntactic analysis in which SVCs involve grammaticalization of one of the verbs sequences. This grammaticalized form serves as an aspect marker, heading an aspect projection at the left periphery of the argument structure projected by the non-grammaticalized verb. This study offers a significant contribution to the understanding of SVCs in sign languages, demonstrating the intrinsic complexity of Libras grammar. Moreover, it opens new avenues for research in the field of sign language linguistics and for a more robust characterization of SVCs in natural languages.