Colors are ubiquitous, especially in the world of brands. Colors help managers create brand identities, establish brand perceptions, attract consumers to their brands and increase brand recognition. Therefore, managers in both for profit and not-for-profit organizations invest ample time and cost in deciding colors for their brand stimuli. However, due to the limited theoretical frameworks available in the color literature, managers are compelled to stick to established color norms. The “Arousal Theory of Color” is one of those frameworks, which proposes that warm and highly saturated single colors drive arousal (Crowley,1993). However, in the recent past, several brands are breaking away from single colors and are exploring multiple colors or color combinations to make them stand out in the market (Google, NBC, Nike, Bear Republic etc.). Yet limited research has investigated the underlying theoretical process between multi-colored stimuli and arousal. Drawing upon visual complexity theory, arousal theory of color, and psychedelic color theory, this dissertation explores how multi-colors impact vibrancy, complexity, arousal, and purchase intentions. Essay 1 explores how marketers can use cool colors on brand logos to increase arousal instead of sticking to warm colors. Drawing on visual complexity theory, five experimental studies (4 controlled experiments that examine fictitious brand logos and 1 Facebook experiment that test different logo color conditions of a not-for-profit initiative) show that the use of multiple cool colors increase the logos’ visual complexity. This in turn, drives higher arousal levels compared to logos made up of single cool colors and has a subsequent impact on brand excitement and consumer’s willingness to purchase the brand. Essay 2 extends Essay 1’s findings by examining the types of color combinations that are most effective in driving visual complexity, vibrancy, and arousal. Drawing on visual complexity and psychedelic art theories, two studies (one large scale study where 793 logos (color combinations) were tested with over 2,000 participants, and one study that investigated complex color patterns of real IPA beer brand packaging) show that average warmth or coolness of color combinations (measured by wavelength), the number of colors and contrast measured by the distance between colors impact stimuli’s visual complexity, vibrancy, and consumer arousal while warmth has a stronger impact on color vibrancy and arousal. Moreover, color vibrancy was found to play a prominent role in mediating the relationship between properties of color combinations and arousal, which thereby drives willingness to purchase. This dissertation contributes to the color literature by deeply investigating colors’ visual complexity, vibrancy, and impact on arousal by proposing alternative ways that colors can be used to drive arousal and the marketing impact of this arousal. In doing so, this work investigates theoretical processes between the novel area of multiple colors (color combinations) and arousal and provides new insights about the effects that color-driven arousal through vibrancy and complexity can have on consumer behavior. Additionally, this dissertation will help managers make more informed decisions about colors for their products and communication.