A survey of 216 adult Macau citizens aged 18 or above was conducted to investigate the correlation between the five facets of the Big Five Personality, Frequency of Personal Contact, Frequency of Mobile Instant Messenger (MIM) Use, MIM Dependency, Belongingness Needs Satisfaction, and Esteem Needs Satisfaction. Extroversion was found to be positively correlated with and significantly predicted Frequency of Personal Contact and Frequency of MIM Use. At the same time, it also served as an important predictor of having personal contact and using MIM. Neuroticism was also negatively correlated with and significantly predicted the Frequency of Personal Contact. Conscientiousness and Neuroticism had positive correlations with MIM Dependency in the Compulsion facet. Agreeableness had a negative correlation with MIM Dependency in the Negative Effect facet, while Neuroticism was found to have a positive relationship with that. Frequency of Personal Contact and Frequency of MIM Use were both found to be positively correlated with and significantly predicted Belongingness Needs Satisfaction, Esteem Needs Satisfaction from both Others and Self.