Answer: is exactly the opposite. The colonization led to imperialism. That is why Spain, that never was an empire, became one (in Europe, only for a little while, when Charles I of Spain was also Charles V of the Holy Roman Empire, ). And Portugal, a little country, became an empire by colonizing Brazil. Or Netherlands, to quote from Wikipedia: The Dutch Empire (Dutch: Het Nederlandse Koloniale Rijk) comprised the overseas colonies, enclaves, and outposts controlled and administered by Dutch chartered companies, mainly the Dutch West India and the Dutch East India Company, and subsequently by the Dutch Republic (1581-1795), and the modern Kingdom of the Netherlands since 1830.[1]
So it seems that you are kind of biased - imperialism is something bad, that led to colonization. Wrong! It was the opposite: the colonization (need for certain resources, like spices), triggered the race for discovering new lands, and exploiting their natural resources, other than spices.
Imperialism was not something good or bad, but it was a stage in the history of mankind. Europeans were in the position to conquer the rest of the world - and it was not always like that - Mongol invasions (Genghiz Khan, Timur Lenk) were far worse than what Europeans did. The Chinese were more developed than Europeans until XVIth century, when the Mandarins took over the Eunuchs at the Imperial Court and decreed unlawful shipbuilding. Japanese closed the access for information and allowed minimal trade with the Europeans, until Commodore Perry forced it to open themselves in 1854.